Former B1A4 leader Jinyoung is turning heads with his physical transformation in the series ' Who Is She '.

In a scene that's going viral online, Jinyoung is seen working out shirtless, his muscles gleaming under the lights as he sweats profusely. One fan shared photos and clips of the scene, commenting, " He's sweating so much... His face remains soft like a fawn's, but his body is incredibly muscular. "

Jinyoung's unexpected transformation has won over many fans, amazed at how much his image has evolved since his days with B1A4, going from the boy-next-door image to that of an irresistible seducer.

The reactions were not long in coming:

" Oh my God."

" What is this series? Jinyoung is amazing.

" That's the Jinyoung I know! When he was younger, he was so thin that people called him Grandpa...

" I was a BANA too. It's been a long time since we called him Grandpa. Lol.

" Grandpa... It's been a long time.

" I was shocked to see him in 'Who Is She'.

" Oh la la.

" It's legendary.

" What happened to him? He's so sexy.

" That's Jinyoung from B1A4, right?

" Oh my, oh my.

" Grandpa has become super sexy.