Julia Roberts shares rare photo with husband Danny Moder to celebrate 21st anniversary: 'True love'

Julia Roberts may be a successful actress with a flourishing career in Hollywood, but she's also managed to keep her family life filled with love and away from the spotlight. The award-winning actress and her husband, cinematographer Danny Moder, have spent decades together and share three children, 18-year-old twins Phinneas and Hazel, and son Henry, 16. The "Pretty Woman" star is notoriously private about her love life but recently celebrated her 21st wedding anniversary with her husband in a sweet Instagram post. She posted a picture of the two sharing a passionate kiss and captioned it, "21 #truelove #heckyeah #fromhereonout," followed by exploding stars emoji.

According to PEOPLE, the "Notting Hill" star married Moder, 54, in a private ceremony on July 4, 2002. Two years before that, the pair met on the sets of the film "The Mexican," where Moder worked as a cameraman, filming Roberts' romantic scenes with Brad Pitt. As for their secret wedding, family members and close friends answered an invitation to "celebrate Independence Day," which turned out to be the couple's wedding!

As the realization spread, "there was a cheer, a sort of wave of cheers that echoed against the mountains," one close friend told PEOPLE. "Danny got down on one knee and said, 'In front of everyone we love, I want to know, will you marry me?' And Julia grabbed her heart and said, 'Yes, yes, yes.' And all the guests were saying 'Yes, yes, yes' along with her. The canopy was billowing. It was such a magical, intimate gathering. It felt like we were eavesdropping, like we were invited into someone's secret."

The happily-married couple has since preferred to keep their relationship and family out of the limelight. Last year, Roberts opened up about family life in an interview with CBS Sunday Morning. "When I'm not working, [being a homemaker] is my full-time job. It isn't rainbows and kittens every day, but it does bring me a lot of joy," Roberts confessed. "The life that I've built with my husband. The life that we've built with our children. And that's the best stuff, to come home at the end of the day triumphantly to them."

The "Erin Brockovich" star revealed that the couple keeps their romance alive by writing love letters to stay in touch when they are away from home, even to this day. She recalled that the first letter he ever wrote her was seven pages long, which she has still kept safe. "And it's something Danny and I have always done. The first letter he ever wrote me, which was seven pages long, I still have it tucked away. One day I'll show it to Hazel and say, 'That's what you're looking for,'" Roberts shared. While she was in Australia for 62 days filming "Ticket to Paradise," she found it challenging to be away from family. "I wrote a lot of letters," she said, instead of just sending an e-mail or texting. "Yeah, but that's kinda boring, and they don't get the cool stamps," Roberts said about why she prefers letters over electronic mail.