Gene Simmons is OFFICIALLY MARRIED!

Gene Simmons and Shannon Tweed have OFFICIALLY tied the knot!

After 28 years together, the KISS bassist, 62, married his longtime girlfriend in an private ceremony outside on the crystal lawn at the Beverly Hills hotel on Saturday. The couple's guests cheered when Simmons said "I do" to his partner.

Tweed, 54, walked down the aisle in an ivory Priscilla of Boston gown – one of three dresses she chose for the big occasion – and carried a bouquet of ivory garden roses.

The couple exchanged vows they wrote themselves in front of 400 guests including Hugh Hefner, Bill Maher and KISS member Paul Stanley.

Also in attendance were the couple's two children Nick, 22, and Sophie, 19, who was the maid of honor.

And their planned first dance is quite fitting for a couple who have been together for almost three decades: "At Last" by Etta James, to be performed by their daughter Sophie.