Sam Taylor-Wood to wed 19-year-old lover Aaron Johnson

Review: Nowhere Boy

A spokesman for the couple confirmed their engagement today and said they are "very happy".

The artist split amicably from her art dealer husband, Jay Jopling, last year and began seeing Johnson, a relative unknown, earlier this year.

Gallery: Nowhere Boy premiere

The Evening Standard revealed their relationship after they appeared at the Cannes Film Festival, where she was promoting Nowhere Boy, in May. The film, which tells of Lennon's early years, has been warmly received by critics.

Johnson, from High Wycombe, has been praised for his role as the teenage Lennon. He has been acting since 2001 and has had parts on television and film roles including The Illusionist and Angus, Thongs and Perfect Snogging.

After his divorce, Jopling, who owns the White Cube gallery and represents Damien Hirst and other former stars of the Young British Artists movement, went on to have a short relationship with Lily Allen, 22 years his junior.

Like other YBAs Damien Hirst, Jake Chapman and Sarah Lucas, Taylor-Wood studied at Goldsmiths and was taken under the wing of Charles Saatchi. Her work includes her short film of David Beckham sleeping.

Her career in the Nineties was marked by extremes — in 1997, she and Jopling married and she gave birth to their older daughter. Later that year she was nominated for the Turner prize, and diagnosed with colon cancer. Three years later she was diagnosed with breast cancer, which led to her self-portrait about her recovery, Single Breasted Suit with Hare, which hangs at the National Portrait Gallery.

Jopling still represents his former wife and was at the Leicester Square premiere with his girlfriend, writer Rachel Barrett. The couple's daughters, Angelica, 12, and three-year-old Jessie, were also on the red carpet. Both had roles in the film so they could spend time on set with their mother in Liverpool.

Taylor-Wood last night dedicated the film to Anthony Minghella, who at the time of his death in 2007 was producing her first short film Love you More.

Nowhere Boy is Taylor-Wood's first feature and tells of the complex relationships between Lennon and his mother, played by Anne-Marie Duff, and his aunt (Kristin Scott Thomas) who raised him.

The director and her young star will attend another premiere in Liverpool next month, before the film goes on general release on Boxing Day.