When he finally took the stage, his band played his 1978 hit “Grease” and his backup singers sang and danced while he attempted to lip sync.

Despite his efforts, he could not keep up with the words.

Later, during “Can’t Keep My Eyes Off Of You,” Valli snaps his fingers, but not along to the beat of the song while shakily holding his microphone.

Fans expressed their concern for the 90-year-old singer.

“The old crooner needs to pack it in. We love em but please don’t remember him like this,” someone wrote on Instagram.

“Yes, this is sad. He is a legend and shouldn’t be subject to this humiliation,” a fan commented on X.

“That’s rough. Hard to let go. Much respect to Frankie.”

“All due respect to Frankie Valli but this is a shame. My musical heroes are pretty old now but I hope they gracefully retire before it comes to this.”

Despite everyone’s concerns, a representative for Valli told The Post, “Frankie is doing just fine and super happy to still be performing. The audiences are filling venues and listening to some great music.”

“Frankie is doing what he loves to do at 90,” they said. “We should all be so lucky.”