Fantastic Four star Alba pregnant

Alba and Warren met on the set of the first Fantastic Four film

Jessica Alba, star of the Fantastic Four movies, is expecting her first child with boyfriend Cash Warren.

"Jessica and Cash are expecting a baby in late spring [or] early summer," her spokesman told the People.com website.

Alba, 26, has been dating Warren since autumn 2004. The pair met on the first Fantastic Four film, on which Warren, 28, worked as a director's assistant.

Alba, recently seen in the comedy Good Luck Chuck, was named the sexiest woman in the world by FHM readers last April.

The actress played Sue Storm, aka the Invisible Girl, in 2005's Fantastic Four and its 2007 sequel.

Her other films include Sin City, Into the Blue and current US release Awake.