Justin Timberlake has confirmed his wife Jessica Biel is expecting a baby by posting a picture of himself caressing the actress’ bump on his Instagram account.

The Mirrors hitmaker – who celebrated his 34th birthday on Saturday (31.01.15) – took to his Instagram account to thanks fans for their kind words and share the couple’s happy news with his seven million followers but added he is yet to find out the sex of the baby

He wrote alongside a photo of himself caressing the actress’ bump: “Thank you EVERYONE for the Bday wishes!

“This year, I’m getting the GREATEST GIFT EVER. CAN’T WAIT. #BoyOrGirl #YouNeverKnow #WeDontEvenKnow #WeAreTakingBets (sic).”

The news follows speculation Jessica, 32, was expecting a child after she was spotted enjoying lunch in Los Angeles with a noticeable bump earlier this month.

The brunette beauty – who is thought to be around five months along – is said to be “feeling really good” and is doing her best to stay fit and healthy throughout her pregnancy

A source recently told E! News: “She’s in her third trimester now and feeling good. She has stayed active during her pregnancy and tried to get in as much exercise as possible.

“She loves going hiking or on walks. She also does yoga at home and light stretching. She has spent a lot of time at home and plans to slow down on traveling in the next two months… she’s embraced being a homebody and taking it easy.

“She has been having deliveries from local farms so she can eat fresh organic produce and be as healthy as possible throughout the pregnancy.

“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.”