Cynthia Erivo Jumps In to Protect Ariana Grande From Wild Fan at ‘Wicked’ Premiere

Cynthia Erivo quickly jumped in to protect her!

It all went down Thursday ... as Ariana, Cynthia, Michelle Yeoh and Jeff Goldblum were all hand-in-hand, greeting fans on the yellow carpet at Universal Studios Singapore.

Check out the video ... as Ariana greets a fan, a man on the opposite side suddenly jumps the barricade and beelines straight for her -- throwing his arm around her and jumping up and down with a big smile.

Needless to say ... Ariana and Michelle both look shocked, but Cynthia wastes no time getting between the wild fan and Ariana -- putting hands on his shoulders and forcing him off AG.

Security then steps in and removes the fan ... as Cynthia and Michelle comfort Ariana.

As the man is carried off by security guards ... he's met with a chorus of boos from other fans. It appears the guy is known for these stunts ... he's believed to be an online personality called "Pyjama Man" who posts videos of himself bum-rushing performers onstage and goofing off in public on TikTok.