On Saturday, Jan. 31, Justin Timberlake not only celebrated his birthday, but he also took to Instagram to confirm he and his wife, Jessica Biel, have a baby on the way.

Timberlake posted a photo of himself kissing Biel's pregnant belly and asked his fans to guess what gender his first child would be.

The "Mirrors" singer revealed he and Biel chose to not know the baby's gender until the birth.

Check out Timberlake's Instagram photo below.

E! News reports Biel is five-months pregnant and is taking extra precaution to ensure she has a smooth and healthy pregnancy.

"She's in her third trimester now and feeling good," a source said. "She has stayed active during her pregnancy and tried to get in as much exercise as possible."

"She has been having deliveries from local farms so she can eat fresh organic produce and be as healthy as possible throughout the pregnancy," the source added. "Being healthy is really important to her. She is very aware of the importance of eating well. She wants to have the best pregnancy possible."

Prior to the confirmation, there had been previous rumor reports Biel and Timberlake were expecting back in October. RadarOnline obtained photos of Biel walking along the beach in Australia appearing comfy and noticeably bigger around her midsection.

At the time, a source said, "[Biel is] at least three months pregnant, and she's due in April!"

Biel's alleged baby bump also made headlines in September when she appeared in the "7th Heaven" cast reunion photo tweeted out by her now controversial co-star Stephen Collins, Inquistr reported.

"If you pay close attention to Jessica Biel in the picture, it appears as if there is a concealed baby bump bulging out from underneath her dress," an Inquistr writer wrote at the time.

Timberlake shared an equally adorable image on his Instagram a few weeks ago. To wish his mother a happy birthday, he posted a throwback picture of the two.