Justin Timberlake Celebrates His '2 Greatest Gifts' on Father's Day as He Pens Heartfelt Message to Sons

Justin Timberlake penned a heartfelt Father's Day message this year in honor of his boys.

Celebrating the special day on Instagram, the 43-year-old "Mirrors" singer uploaded photos of his sons Silas, 9, and Phineas, 3½  — whom he shares with wife Jessica Biel —  and called the boys his "2 greatest gifts."

In one of the two images he posted, Timberlake held the back of Silas' head in what appeared to be a backstage on the singer's tour — as Silas wore a "Forget Tomorrow World Tour" jacket. In the other, he held his younger boy on his shoulders while proudly looking up at him.

"I learn more about myself everyday just because you both chose me to be your Daddy. I will always be there for you through your peaks and valleys… to lift you up and show you how high you can take this life and to pick you up when you fall," Timberlake wrote, before cracking a quick joke.

"And, of course, to flood you with insufferable Dad-jokes all along the way. I love you both so much. Thank you for giving me my biggest purpose."

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Timberlake then revealed exactly what he and his family are planning for the big day. "Now… for today: let’s play a game where we all just chill and let Dad watch the final round of The US Open ⛳️," he joked.

"Cheers to all the Dads out there Dad-ing! I salute you! 🫡 "

The *NSYNC alum also shared an Instagram Reel where he revealed he was "officially whooped" after his latest tour date in Miami. "Back at it next weekend. Happy Father's Day to all the dads out there," he said in the clip.

Wife Biel shared her own collection of photos, leading with one of Phineas perched on his dad's back. She wrote, "You’re so many things to so many people. But to us you are THE ROCK. The rock we climb on, we lean against. The rock that shades us from the sun. And when we recline on you, as we always do, hopefully our butts will keep you eternally grounded and warm. We LOVE YOU 🪨❤️"

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Earlier this month, Biel spoke to PEOPLE about her debut children's book, A Kids Book About Periods, which seeks to de-stigmatize the topic of menstruation for young readers. The actress and producer opened up about how she's teaching that lesson in her own home.

"My son and I read half of the book for the first time this morning, it was really cool to see him listening," Biel, 42, told PEOPLE exclusively of Silas.

"He would read a page and I would say, 'Okay, so this is what's happening.' And I said, 'Okay, this is the period. This happens to me every month. And it'll happen to people in school,' " she said.

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Biel continued, "This was... The best part, is he kind of was like, 'Oh, that's weird.' I said, 'Yeah, it is kind of weird, but trust me, it's weird for me too. When it happens to me, it's still weird.'"

"And I said, 'Think about it. There's somebody at school that might have their period and they might need your help or support someday, and it's really going to be important for you to understand what's happening so you can help a friend if they need something,' " she concluded.

Earlier this year, Timberlake appeared on The Tonight Show Starring Jimmy Fallon, where he called his sons "both so cute," a sentiment that his longtime friend Fallon agreed with. "They're both so cute. You lucked out," Fallon said. "Yeah, you got a good kid."

"They run our house. It's crazy," Timberlake admitted. "It's crazy."