Uma Thurman is reportedly expecting a baby girl.

The actress and her boyfriend Arpad Busson confirmed they are to become parents last week.

A source has now told Life & Style that the pair have already discovered the sex of the impending arrival.

"Uma is having a baby girl," the person told the publication.

When news of Uma's pregnancy was first reported, another insider spoke to the publication about how happy the couple are.

"She's happy and just a few months along right now," the insider said. "She's due in late summer."

Uma is already mother to Maya, 13, and ten-year-old Levon, her children with her ex-husband Ethan Hawke.

Rumours she was expecting began to surface after she made an appearance at the recent New York Fashion Week. The former model was in the front row of the Tommy Hilfiger runway show on February 12 and was unusually covered up in a baggy shirt and a loose fitting jacket.

Uma, 41, and Arpad have been together since 2007. They went their separate ways in 2009 but have reunited and are now stronger than ever.