Karl-Anthony Towns has another ring to celebrate ... tying the knot with Jordyn Woods at a Malibu wedding with enough star power to fill several courtside rows.

The longtime couple exchanged vows Saturday during an outdoor ceremony overlooking the Pacific Ocean ... surrounded by an elaborate spread of white flowers and their family and closest friends.

The black-tie ceremony may have been intimate, but the guest list was anything but low-key ... with some of Hollywood's biggest names dressing in black for the occasion.

Justin and Hailey Bieber were there ... along with Kylie Jenner and Timothée Chalamet, Ben Stiller, Teyana Taylor, Michael B. Jordan and more.

KAT's NBA friends and teammates also watched him and Jordyn say "I do" ... before the newlyweds posed for photos with family and guests.

The formalwear didn't last all night ... Teyana and other guests reportedly were spotted leaving in custom "Married in 15" hoodies while carrying Fanatics goodie bags and In-N-Out cups.

One more ring for KAT ... this one's for life.