James Marsden is expecting a baby with model Rose Costa, it has been reported.

The actor is believed to have been romancing the Brazilian beauty since late last year, following his divorce from his wife of 11 years in October 2011.

According to the New York Post, the surprise pregnancy happened after James and the 24-year-old model spent the night together in Miami.

Rose is believed to be three months pregnant and planning to keep the baby.

The news of the unexpected pregnancy is said to have left the model's ex-boyfriend, actor Chris Santos, heartbroken.

The couple had been living together in Los Angeles for two years when Rose moved to New York to pursue her career. She met James in the city and they started dating, but Chris won her back and the pair returned to LA together.

"Santos found out and flew to New York to win her back. They spent the holidays together and got a new apartment," a source told the New York Post.

Rose is believed to have met James again in Miami a few months later, resulting in Chris confronting her.

"She confessed everything. She told him they hooked up one night, one time," the source added.

The revelations are believed to have split the couple and Santos reportedly moved out of their apartment immediately.

However, other sources report the pair had broken up before Rose got involved with James.