The former The O.C. star had to dismiss reports she was with child last month (Feb10) after she was photographed heading into a medic's office wearing an oversized raincoat.
And Bilson admits she and fiance Hayden Christensen found the whole story "hilarious".
She tells Cleo magazine, “It was like, 'Really? Where does this come from?' I went to the doctors because I have sinus problems. I walk out and it was raining, so I had a big raincoat on - so (the tabloids) thought I was pregnant.
"I had Q-tips stuck up my nose because I’m having sinus issues. If you want to think I’m pregnant, then fine!"