Simon Cowell had a massive excuse to throw a bit of a party last night, after all he has just signed one of the biggest stars in the world to The X Factor USA.

Yes, after weeks of rumours and speculation, Britney Spears was finally officially confirmed as a judge on the second of the US version of the show.

britney spears

And after the unveiling of the new judging line-up yesterday at Fox's Upfronts, which also saw Demi Lovato join Simon and L.A. Reid on the panel, they headed out for a few tipples to celebrate.

britney spears

The new X Factor crew headed to ABC Kitchen where Britney changed out of her short white dress she wore earlier in the day and slipped into a purple number.

britney spears

And by the look of it, Simon had clearly got a bit over excited at the thought of sitting next to Britney, spilling his drink down his (deeply unbuttoned) white shirt.

simon cowell

On announcement she would be replacing ousted judges Nicole Scherzinger and Paula Abdul, Britney said: "I couldn't be more excited to join The X Factor judging panel. I'm a huge fan of the show and now I get to be a part of the action. Simon and LA better watch out!"

Speaking of why he chose Britney and Demi, Simon added: "I'm absolutely delighted Britney and Demi are joining us. Britney remains one of the biggest stars in the world, she's talented, fascinating - and I believe she knows exactly how to spot The X Factor."

We have a feeling Britney on X Factor is going to make uh-may-zing telly, but whether that's in a good way or in a car crash way, we haven't quite decided...

> IN PICS: BRITNEY JOINS X FACTOR USA

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  • Fox 2012 Programming Presentation Post-Show Party

    NEW YORK, NY - MAY 14: Simon Cowell and Britney Spears attend the Fox 2012 Programming Presentation Post-Show Party at Wollman Rink - Central Park on May 14, 2012 in New York City. (Photo by Dave Kotinsky/Getty Images)

  • Britney joins X Factor USA

    (Pic: WENN)

  • Britney joins X Factor USA

    (Pic: WENN)

  • Britney joins X Factor USA

    (Pic: WENN)

  • Britney joins X Factor USA

    (Pic: WENN)

  • Britney joins X Factor USA

    (Pic: WENN)

  • Britney joins X Factor USA

    (Pic: WENN)

  • Britney joins X Factor USA

    (Pic: WENN)

  • Britney joins X Factor USA

    (Pic: WENN)

  • Britney joins X Factor USA

    (Pic: WENN)

  • Fox 2012 Programming Presentation Post-Show Party

    NEW YORK, NY - MAY 14: (L-R) L.A. Reid, Demi Lovato, Simon Cowell, and Britney Spears attend the Fox 2012 Programming Presentation Post-Show Party at Wollman Rink - Central Park on May 14, 2012 in New York City. (Photo by Dave Kotinsky/Getty Images)

  • Fox 2012 Programming Presentation Post-Show Party

    NEW YORK, NY - MAY 14: Simon Cowell and Britney Spears attend the Fox 2012 Programming Presentation Post-Show Party at Wollman Rink - Central Park on May 14, 2012 in New York City. (Photo by Dave Kotinsky/Getty Images)

  • Britney joins X Factor USA

    (Pic: PA)

  • Britney joins X Factor USA

    (Pic: PA)

  • Britney joins X Factor USA

    (Pic: PA)

  • Britney joins X Factor USA

    (Pic: PA)

> IN PICS: FOX 2012 PROGRAMMING PRESENTATION

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  • Lea Michele

    Actress Lea Michele attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

  • Fox 2012 Programming Presentation Post-Show Party

    NEW YORK, NY - MAY 14: Lea Michele attends the Fox 2012 Programming Presentation Post-Show Party at Wollman Rink - Central Park on May 14, 2012 in New York City. (Photo by Dave Kotinsky/Getty Images)

  • Fox 2012 Programming Presentation Post-Show Party

    NEW YORK, NY - MAY 14: Lea Michele attends the Fox 2012 Programming Presentation Post-Show Party at Wollman Rink - Central Park on May 14, 2012 in New York City. (Photo by Dave Kotinsky/Getty Images)

  • Naya Rivera

    Actress Naya Rivera from "Glee" attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012, in New York. (AP Photo/Evan Agostini)

  • Becki Newton

    Actress Becki Newton from "The Goodwin Games" attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

  • Cat Deeley

    Host of "The Choice" and "So You Think You Can Dance" Cat Deeley attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

  • Cat Deeley

    Host of "The Choice" and "So You Think You Can Dance" Cat Deeley attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

  • Naya Rivera

    Actress Naya Rivera from "Glee" attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

  • Randy Jackson, Ryan Seacrest

    Randy Jackson, left, and Ryan Seacrest from "American Idol" attend the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

  • Natalie Zea

    Actress Natalie Zea from "The Following" attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

  • Gordon Ramsay

  • Zooey Deschanel

    Actress Zooey Deschanel from "New Girl" attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

  • Fox 2012 Programming Presentation Post-Show Party

    NEW YORK, NY - MAY 14: Zooey Deschanel attends the Fox 2012 Programming Presentation Post-Show Party at Wollman Rink - Central Park on May 14, 2012 in New York City. (Photo by Dave Kotinsky/Getty Images)

  • Fox 2012 Programming Presentation Post-Show Party

    NEW YORK, NY - MAY 14: Kevin Bacon attends the Fox 2012 Programming Presentation Post-Show Party at Wollman Rink - Central Park on May 14, 2012 in New York City. (Photo by Dave Kotinsky/Getty Images)

  • Fox 2012 Programming Presentation Post-Show Party

    NEW YORK, NY - MAY 14: Zooey Deschanel attends the Fox 2012 Programming Presentation Post-Show Party at Wollman Rink - Central Park on May 14, 2012 in New York City. (Photo by Dave Kotinsky/Getty Images)

  • Darren Criss

    Actor Darren Criss from "Glee" attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

  • David Boreanaz

    Actor David Boreanaz from "Bones" attends the FOX network upfront presentation party at Wollman Rink, Monday, May 14, 2012 in New York. (AP Photo/Evan Agostini)

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