Denise Richards and Richie Sambora are officially back on!

The duo, who dated right after splitting from their ex-spouses Charlie Sheen and Heather Locklear, hit the red carpet together last night at the Golden Heart Awards Gala -- where they made their public debut as a couple ... again.

At the event, 41-year-old Denise told E! "This is a big night for Richie, so I'm here to support him. It's really important work that he does."

Sambora, 53, added "We're back on. It's all good."

Joining the couple on the red carpet was Richie's 14-year-old daughter with Locklear, Ava, who looked gorgeous in a short white dress.

As for Heather herself, she's been keeping a low profile since her 911 emergency back in January -- but was spotted on May 4 looking healthy while working out with a friend at an L.A. park.