"Happy Bday to the sweetest, most GORGEOUS, goofiest, most BAD-ASS chick I know," he posted Tuesday along with a photo of the two of them on Instagram. "You make me smile 'til it hurts. I love you like crazy! --Your Huz."
The couple celebrated Tuesday night with no more than 10 people assembled at the home of Biel's buddy Estee Stanley, E! News reported.
The evening, which a source dubbed "mellow," saw her very pregnant in a black-and-white maxi dress with a black short-sleeve coat and him in jeans and a button-down. He toted her gifts as they left the party around 11:30 p.m., E! said.
Sounds just about right for a woman who's reportedly only weeks away from giving birth.