Kevin Richardson is looking back at a song with extra special meaning. The Backstreet Boys member, 53, recently shared the story of the band's song "Back to Your Heart," off of 1999's Millennium.

The Backstreet Boys are in the midst of a sold-out spectacle at Sphere Las Vegas. Kevin Richardson gives the inside scoop to USA TODAY.

Kentuckians Kevin Richardson and Brian Littrell are headed to Las Vegas as part of The Backstreet Boys' "Into the Millennium" residency.

The Backstreet Boys are in the midst of a sold-out spectacle at Sphere Las Vegas. Kevin Richardson gives the inside scoop to USA TODAY.

The Backstreet Boys—comprised of Nick Carter, Howie Dorough, AJ McLean, Brian Littrell, and Kevin Richardson—skyrocketed to fame alongside similar groups like *NSYNC and 98 Degrees.

Kevin Richardson delighted a fan with an 'Ls down' gesture at Las Vegas Sphere during the Backstreet Boys' 'Into the Millennium' residency.

The new Backstreet Boys Fisher-price Little People toy set features the bandmates in their looks from the "I Want It That Way ...

The Backstreet Boys are in the midst of a sold-out spectacle at Sphere Las Vegas. Kevin Richardson gives the inside scoop to USA TODAY.

The Backstreet Boys are in the midst of a sold-out spectacle at Sphere Las Vegas. Kevin Richardson gives the inside scoop to USA TODAY.