Los Angeles, Oct 2 (IANS): Actor Armie Hammer has accidentally revealed that his wife Elizabeth Chambers is expecting a son.

Hammer, who appeared on the popular TV show "Jimmy Kimmel Live!" on Thursday night, was joking with Kimmel about some of the funny names his unique surname sets up -- but he only gave male examples, reports aceshowbiz.com.

"You can find out now at nine weeks, which is really bizarre. They do a blood test. They test if there are hormones in there. They go, 'Oh, you've got testosterone -- so you've either got b***s or you're having a baby boy," Hammer said.

Asking about any potential names, Kimmel joked: "When your last name is Hammer, you really have a wide variety of options."

The actor responded: "We are thinking Jack -- Michael Charles and he can just go by MC."

He then realised his slip-up and said: "I think I just gave away our baby name? I'm in so much trouble!"

The yet-to-be born child will be Hammer's second one with Chambers. The couple welcomed their first child, a daughter named Harper, in December 2014.