Adam performed Saturday night with his band, Maroon 5, at Shaquille O'Neal's annual fundraising gala, "The Event." It went down at the MGM Grand Garden Arena in Vegas.

Adam had some company onstage ... Shaq joined him as the band performed "This Love."

Social media judgments be damned ... it was a great evening that benefited the Boys & Girls Clubs and Communities in School. One hundred percent of the proceeds are going to charities.

Shaq has been squarely in Adam's corner, making it clear ... "Adam is a personal friend of mine. He's always been a great guy."

As for the scandal, Shaq said, "It is not my job to say, 'You did this. You did that. You shouldn’t have did this. You shouldn’t have did that,'" he continued. "As far as I can say, he’s coming to help kids out this weekend. He’s a good man in my book."

Adam and his pregnant wife, supermodel Behati Prinsloo, are presenting a united front. They've been seen out together, and got on a private jet a few days ago. It's unclear if they were going to Vegas, but that seems likely considering Behati was at the fundraiser.