The Real Housewives of Beverly Hills star, 51, and Rod Stewart's 31-year-old son were in the crowd for the Timothy Bradley - Ruslan Provodnikov fight at the Home Depot Center in Carson, CA.
"They were sitting together ringside and totally making out with not a care that they were surrounded by people," an eyewitness tells us.
"I would have totally thought it was for publicity if it wasn't for the fact that we were at a fight, and not courtside at the Lakers," the source laughs.
"They were just going at it!"
Just last week the couple was reported to have split but Adrienne apparently wants everybody to know that's not the case.
Early Sunday morning, Adrienne decided to share the news with her fans, tweeting a photo of herself and Sean, cozying up at the fight.
And for those who care about the actual fight -- Bradley won in what is being called a "thrilling" decision over the Russian Provodnikov.