Alyson Hannigan shoots down pregnancy rumors

(CBS) Alyson Hannigan is shooting down rumors that she's pregnant, citing "too much carnival food" as the reason for the speculation.

The "How I Met Your Mother" actress set the record straight on Twitter after she was photographed with a supposed baby bump.

"NO, I'm not pregnant! I just ate too much carnival food, that time of the month, hurt my back & couldn't suck my gut in, & need 2 do cardio!" she wrote on Sunday.

"And I'm NEVER gonna wear that shirt again!!!" she added.

Hannigan, 37, and husband Alexis Denisof are already parents to daughter Satyana, who was born in 2009.

The actress recently finished shooting the next film in the "American Pie" franchise, "American Reunion."

"That's a wrap!!! I had SO MUCH fun!!! I think this one will be the best of the bunch," she wrote on July 28. The movie is due out on April 6, 2012.

"How I Met Your Mother" returns to CBS on Sept. 19. Hannigan's character on the show, Lily, was revealed to be pregnant at the end of last season.