It's hard to believe, but Justin Timberlake just hit the big 4-0!
The 38-year-old shared a series of photos of her main squeeze, including a snapshot of him wearing a birthday crown about to dig in to some pancakes and two more of the couple enjoying some hot dogs at a baseball game and goofing around at a golf course. She ended with a romantic, candid moment of them exchanging a kiss at a formal event.
The mother of two sent some love to her hubby in the post's caption, as well.
"There’s no one I have more fun with, have more laughs with, feel more deeply for, and have more history with," she wrote. "I honor you today, baby. And wish you the most creative and fulfilling year to date."
In the comment section of Biel's post, many of Timberlake's longtime fans who've already entered their 40s welcomed him to the club, and his celebrity friends also sent plenty of well wishes.
Mary Steenburgen, Timberlake's co-star in the 2009 film "The Open Road," wrote: "My love to you both! Happy Birthday JT."
Biel's "7th Heaven" co-star Beverley Mitchell wrote "Happy Birthday @justintimberlake Welcome to 40!"
Parenting coach Nanny Connie, who has worked with Timberlake and Biel, left a loving message for the father of two: "Being blessed to view the 30s in the rearview mirror ..while keeping your hands firmly on the wheel for your 40s bravo son. ... You got this !!!!"
Timberlake's friend and "The Tonight Show" host Jimmy Fallon also sent the singer a birthday message using his signature sense of humor. The 46-year-old posted a clip on Instagram of a recurring "Saturday Night Live" sketch, "The Barry Gib Talk Show," which the pals starred in together.
"Everyone’s talkin’ it up in honor of @justintimberlake’s 40th birthday!!! Love you brother. #BrothersForever #BroFor," Fallon wrote.