Taylor-Wood and Johnson celebrate baby girl

A statement on the couple's behalf said: "Sam Taylor-Wood and Aaron Johnson are happy to announce the birth of their daughter Wylda Rae."

Love blossomed for the couple on the set of Taylor-Wood's movie Nowhere Boy, when Johnson played John Lennon in his early years.

The acclaimed biopic was Taylor-Wood's first foray into directing a feature-length film.

The pair announced their engagement on the night of the film's premiere in October last year and in January they confirmed they were expecting their first child.

Taylor-Wood already has two daughters with her ex-husband, art dealer Jay Jopling.

Despite the 23-year age gap, the couple have said their friends and family are "really supportive" of their relationship.

Taylor-Wood, who has battled cancer twice, said previously: "(They have reacted] really positively. They know how intensely we feel."

Johnson has described himself as "a very lucky man" after landing a breakthrough film role as well as a wife-to-be.

Christopher Mintz-Plasse, Johnson's co-star in the movie Kick-Ass, posted on the website Twitter: "Aaron Johnson's baby was born!! So exciting!"