LOS ANGELES, CALIFORNIA – FEBRUARY 10: (L-R) Brian Littrell, AJ McLean, Nick Carter, Kevin Richardson, and Howie Dorough of Backstreet Boys attend the 61st Annual GRAMMY Awards at Staples Center on February 10, 2019 in Los Angeles, California. (Photo by Jon Kopaloff/Getty Images)

This weekend, the Backstreet Boys celebrated a major milestone of a whopping 26 years together.

Nick Carter, Howie Dorough, AJ McClean, Kevin Richardson and Brian Littrell celebrated their anniversary Saturday with an adorable throwback post of their earliest days together. On social media, they shared the image of themselves in a high school gym when they were just starting out.

“On this day in 1993 we became the Backstreet Boys. From performing in high school gyms to heading out on a world tour this summer (plus a #1 album!!), never could the five of us have imagined what the past 26 years would hold,” the group wrote. “Thank you all ❤️ Here’s to many more years! #KTBSPA #BSB26.”

And after almost three decades, 130 million records sold and seven GRAMMY nominations, the group is showing no signs of slowing down either. Their latest album, DNA, also debuted at number one on the Billboard charts earlier this year.

The guys also celebrated their decades together recently with The Backstreet Boys: The Experience at the GRAMMY Museum in LA.

Nick Carter told Entertainment Tonight: “We had to dig into some of our old warehouses and storage units to find some of these things that we didn’t know existed anymore. I mean we went all the way back to our Millennium tour, found the blue outfits that we wore…Just things that people hadn’t seen before, or hadn’t seen in a long time. We put together a great collection of things that I think people will be able to remember and recall, and celebrate with us.”

The guys are currently wrapping up their Las Vegas residency, Larger Than Life, at Planet Hollywood. Just last night, Aerosmith’s Steven Tyler joined the group onstage to serenade his girlfriend. The guys sang “Shape of My Heart,” in the adorable moment and later expressed their excitement.

It doesn't get more dope than this dude and the surprise he pulled at the show last night! Was awesome to have you and @theaimeeann there!! #BSBVegas #DeucesAreWild

52.3k Likes, 528 Comments - AJ McLean (@aj_mclean) on Instagram: "It doesn't get more dope than this dude and the surprise he pulled at the show last night! Was..."

BSB is also set to head out on the DNA tour, which kicks off next month.