Natascha McElhone has admitted it was her 11-year-old son who inspired her to accept a role in football movie Believe.

The 44-year-old actress is a single mother to three sons - Theodore, 14, Otis, 11 and five-year-old Rex - after her husband Martin Kelly died suddenly of heart problems in 2008.

Natascha's latest film role is in Believe, a new film about Manchester United legend Sir Matt Busby, and she confessed she felt obliged to say yes for her 11-year-old son, who is "obsessed" with the beautiful game.

"My involvement in this film was sort of a dedication to him," she said.

"We went to Manchester obviously, and he got to go to Old Trafford and see a game in the home ground, which meant the world to him. It was great, a sort of mini-Odyssey for the two of us."

The actress recently completed a four-month run in a West End production of Fatal Attraction, but now the summer holidays have arrived she has no plans to take a break.

She revealed: "No, I need to crack on! When it's [the boys'] summer holidays I can be so much more flexible where and how I work, because we can all go like a gang," she said.

"So I'll probably crack on through and then, when they go back to school, take it easy a bit."

:: Believe is in cinemas now.