The "Suit & Tie" crooner shared the news on Instagram on his 34th birthday on Saturday.
"Thank you EVERYONE for the Bday wishes! This year, I'm getting the GREATEST GIFT EVER. CAN'T WAIT. #BoyOrGirl #YouNeverKnow #WeDontEvenKnow #WeAreTakingBets," he wrote, sharing a pic of himself kissing what appears to be his wife's rotund belly on Instagram.
It's unclear how far along the 32-year-old "7th Heaven" alum is, but E! News reported that she is in her third trimester.
News of the pregnancy broke back in November, though neither Biel nor Timberlake confirmed it. Then, Timberlake's former 'N Sync bandmate Joey Fatone spilled the beans via In Touch about a month later.
The couple wed in Southern Italy in October 2012 after dating on and off for five years. The Emmy- and Grammy-winning Timberlake popped the question in January 2012.
The recurring "SNL" guest star, who will appear on the sketch series' 40th anniversary special on Feb. 15, shared what appeared to be a rare snapshot of himself and wife on his Instagram feed in September when the two celebrated their two-year wedding anniversary, which only hinted that something might be brewing.
"Life moves pretty fast. If you don't stop and look around once in a while, you could miss it," he captioned the photo, quoting "Ferris Bueller's Day Off." The couple are seated on a bench looking at the view with only the back of their heads to camera.
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