Big bumpBig bumpKatharine McPhee has something to tell us.

And it's kiddiewink-related.

But it's not what you might be thinking.

Do you think there's a sprog growing in that tum?

Looks like it, doesn't it?

But it's all a farce.

The faux baby belly is all in the name of her latest film role, House Bunny - where she plays a pregnant lady.

Katharine told Entertainment Tonight "I (do) definitely want to have a baby, and it's fun to just pretend and look in the mirror.

"I think it'll probably hold me off a bit on having a baby.

"Today is the first day I'm wearing the prosthetic belly, which wraps all the way around (to) my back, and it's actually really comfortable.

Katharine McPheeKatharine McPhee shows off her fake baby lump"I'm really enjoying it. It's hot and sweaty though, but it's like method acting.

"(In this project), I'm in my ninth month, so I should be hanging kind of low."

Have a peep at the action on set, which includes Anna Faris in her undies, in our gallery.