Justin Timberlake loves wife Jessica Biel "to the moon and back".

The couple wed in 2012 and welcomed their first child, son Silas, in April 2015. As Jessica marked her 34th birthday on Thursday (03Mar16), Justin posted an adorable tribute to his spouse on his Instagram page.

Alongside a shot of him planting a kiss on his wife's cheek, Justin wrote: "Happy BAE-DAY, baby!! I can't put into words what you mean to me... You are the GREATEST Mommy and Wife a man could ever ask for. I love you to the MOON AND BACK!!! - Your Huz (sic)."

Jessica and Justin enjoy a more private relationship than many of their celebrity peers, but have been seen at various events during the 2016 awards season.

It doesn't seem like the pair are rushing into having another baby anytime soon, as Jessica recently opened up about how difficult she has found motherhood to be.

“He's (Silas) wonderful. He's just a joy,” Jessica said during an interview on Today in October (15). “It's an amazing, amazing experience."

“It's incredibly hard, the hardest job in the world, and I've never been more thankful and grateful to my own mother. Oh, my gosh, I'm going to call her right after this actually and just thank her. What you have to do for your kid - it's an amazing responsibility and the biggest joy ever."

Becoming a parent has also inspired the opening of Jessica's new restaurant Au Fudge - a child friendly eatery. She decided to start the restaurant after realizing just how daunting it could be to head out for a meal with a baby.

“I think it really was my friends who had kids they couldn't go anywhere that they loved," Jessica told Extra this week. (beg29Feb16). "It was either the kids were happy or they were happy, and I couldn’t really join them anywhere because they were at a ball pit or they were at a place that the food options were pizza or fries and that was sort of it, so that’s where the idea came from. We all started talking about it and it was clear this was what was missing.”