Actress Megan Fox is pregnant with her first child, according to a US report.

The Transformers beauty, 25, wed her longtime boyfriend Brian Austin Green in June, 2010 and became stepmother to the 38-year-old actor's son Kassius, who turns 10 on Friday.

But editors at Star magazine allege Fox is now expecting a baby of her own.

A source tells the publication, "They just found out and are incredibly excited. It's still early, so they are only telling close friends and family members... Kassius can't wait to be a big brother."

Representatives for Fox and Green had yet to respond to requests for a comment as WENN went to press.

If the baby report is true, it won't be a surprise for Fox's fans - she recently admitted she can't wait to start a family with Green, telling Cosmopolitan magazine, "I want at least two, probably three (kids). I've always been maternal."