American Pie star Alyson Hannigan is worried her pregnancy is starting to affect her brain - her hormones have left her feeling like a "stoned Koala bear."

The 34-year-old actress is expecting her first child with husband Alexis Denisof and is experiencing a variety of unusual food cravings. However the star is adamant that the worst symptom of pregnancy is the effect it has on her concentration.

She tells TV host Ellen Degeneres, "I get tired a lot and I have pregnancy brain, which I never realized was a thing but it is. I sort of feel like a Koala bear where I'm slightly stoned all the time and I'll say the wrong word. (I crave) ginger ale big time. I didn't drink soda before and suddenly it was like, 'I need a ginger ale,' and surprisingly my mother craved ginger ale when she was pregnant with me as well."

And Hannigan admits that the couple recently found out the sex of the baby, but won't be making the news public. She adds, "We're just not announcing to the world. It seems a little personal."

Hannigan is due to give birth this spring.

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(This news article provided by World Entertainment News Network)