A resurfaced video from the 1991 Jerry Lewis MDA Labor Day Telethon has revealed a hidden musical talent of actor Jason Alexander, best known for his role as George Costanza on the iconic sitcom "Seinfeld." The clip features Alexander performing "This Is The Moment" from the musical "Jekyll & Hyde" with surprising operatic vocals.

Fans have expressed astonishment at Alexander's vocal prowess, with many unaware of his extensive Broadway background. Prior to his "Seinfeld" fame, Alexander won a Tony Award for Best Actor in a Musical in 1989 for his role in "Jerome Robbins' Broadway." His earlier stage credits include originating the role of Joe in Stephen Sondheim's "Merrily We Roll Along" in 1981, starring in "The Rink" in 1984, and appearing in the Neil Simon play "Broadway Bound" in 1986.

Alexander also has experience directing, most recently helming the 2023 Broadway production of "The Cottage." Social media reactions highlighted the surprise, with some users commenting that they initially thought he was performing a comedic bit and that his vocal talent was often overshadowed by his "Seinfeld" character.

The acclaimed actor, 66, who is best known for his role as George Costanza on nine seasons of Seinfeld, wowed with a rendition of This Is The Moment from Jekyll & Hyde, which he performed on the 1991 Jerry Lewis MDA Labor Day Telethon

During his nine seasons on "Seinfeld," which aired from 1989 to 1998, Alexander played the neurotic George Costanza, a role for which he received a Screen Actors Guild Award and was nominated for multiple Emmy and Golden Globe Awards. He also made a cameo appearance in the second season of "Curb Your Enthusiasm."

The role won him a Screen Actors Guild Award for Outstanding Performance by a Male Actor in a Comedy Series; (L-R) Jerry Seinfeld, Alexander, Julia Louis-Dreyfus and Michael Richards

In a 2024 interview, Alexander reflected on his most memorable Costanza moment, citing the season three episode "The Red Dot," where George engages in an office romance with a cleaning woman. He described the storyline and Costanza's reaction as insightful into the character's mindset and a brilliant piece of writing by "Seinfeld" creators Jerry Seinfeld and Larry David.