Good on Rihanna for lending her support to Comic Relief.
The star got behind the Red Nose Day campaign by posing for a picture in one of Stella McCartney's t-shirts especially designed for the charity.
But in true Rihanna fashion she forgot to pop her trousers on beforehand.
Tweeting the snap, Stella McCartney wrote: "Thank you @Rihanna for supporting @rednoseday! You're the best x Stella #RND."
Let's hope there's some money in the charity kitty to buy RiRi a pair of trews.
The t-shirts are available from TKMaxx now.
Want to make a difference? Click here to donate to Comic Relief
Rihanna launches River Island range
Rihanna for River Island Collection Launch - London(01 of32)
Rihanna makes an appearance at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(02 of32)
Rihanna makes an appearance at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(03 of32)
Rihanna makes an appearance at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(04 of32)
Rihanna makes an appearance at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(05 of32)
Rihanna makes an appearance at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(06 of32)
Rihanna makes an appearance at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(07 of32)
Rihanna makes an appearance at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(08 of32)
Rihanna makes an appearance at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna fashion line - London(09 of32)
Rihanna makes an appearance at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna For River Island - Store Launch - After Party At DSTRKT(10 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(11 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(12 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(13 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(14 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(15 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(16 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(17 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(18 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(19 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(20 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(21 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(22 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(23 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch - After Party At DSTRKT(24 of32)
LONDON, ENGLAND - MARCH 04: (EMBARGOED FOR PUBLICATION IN UK TABLOID NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME. MANDATORY CREDIT PHOTO BY DAVE M. BENETT/GETTY IMAGES REQUIRED) Rihanna attends the exclusive after party following the launch of her Rihanna For River Island collection at DSTRKT on March 4, 2013 in London, England. (Photo by Dave M. Benett/Getty Images) (credit:Getty Images)
Rihanna for River Island Collection Launch - London(25 of32)
A model showcases Rihanna's new fashion line at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(26 of32)
A model showcases Rihanna's new fashion line at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(27 of32)
Models showcase Rihanna's new fashion line at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna for River Island Collection Launch - London(28 of32)
A model showcases Rihanna's new fashion line at the River Island store in Oxford Street, London, to promote her new fashion line. (credit:PA)
Rihanna For River Island - Store Launch(29 of32)
LONDON, UNITED KINGDOM - MARCH 04: Rihanna attends as the Rihanna for River Island collection is launched at the Oxford Street River Island store on March 4, 2013 in London, England. (Photo by Stuart Wilson/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch(30 of32)
LONDON, UNITED KINGDOM - MARCH 04: Rihanna attends as the Rihanna for River Island collection is launched at the Oxford Street River Island store on March 4, 2013 in London, England. (Photo by Stuart Wilson/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch(31 of32)
LONDON, UNITED KINGDOM - MARCH 04: Rihanna attends as the Rihanna for River Island collection is launched at the Oxford Street River Island store on March 4, 2013 in London, England. (Photo by Stuart Wilson/Getty Images) (credit:Getty Images)
Rihanna For River Island - Store Launch(32 of32)
LONDON, UNITED KINGDOM - MARCH 04: Rihanna attends as the Rihanna for River Island collection is launched at the Oxford Street River Island store on March 4, 2013 in London, England. (Photo by Stuart Wilson/Getty Images) (credit:Getty Images)