A record-breaking show of Lucian Freud paintings will open until midnight for three days to cope with unprecedented visitor numbers.
The exhibition at the National Portrait Gallery (NPG) has attracted 175,000 people since it opened on February 9, making it the gallery's most popular paying show ever.
The show is latest in a round of 'blockbuster' art shows to enjoy huge success in Britain over the past 12 months, including Leonardo da Vinci at the National Gallery, David Hockney at the Royal Academy and the current Damien Hirst retrospective at Tate Modern.
NPG director Sandy Nairne said he was delighted Freud was proving so popular.
He said: "Visitors are coming to the gallery to experience the sheer brilliance found across seven decades of portraits by one of Britain's greatest artists."
The show includes the last work painted by Freud before he died last July.
The unfinished nude painting, Portrait of the Hound 2011, shows Freud's assistant David Dawson with his dog Eli.
Freud was painting the work shortly before he died at the age of 88.
The show features more than 100 paintings and works on paper, beginning with the British artist's earliest in the 1940s, loaned from museums and private collections around the world.
Freud, grandson of psychoanalyst Sigmund Freud and the brother of the late television personality Sir Clement Freud, was born in Berlin in 1922.
His Jewish family had to flee the city in 1933 and he become a British citizen in 1939.
His key pieces include Girl With A White Dog, Naked Girl Asleep and Reflection (self portrait), while he was particularly known for his paintings of nudes.
The show closes on 27 May.