Grant Gustin, who plays Sebastian Smythe on hit musical TV show Glee, says his character’s desire to break up the show’s young gay couple earned him death threats from fans.

Main character Kurt Hummel, played by Chris Colfer, had found love with Blaine Anderson, played by Darren Criss, when he transferred to his school’s choral rival, Dalton Academy.

But clouds gathered following the arrival of Sebastian, portrayed by Grant Gustin, who set his sights on Kurt’s new boyfriend.

Guston, 22, said at the time his character was “after Blaine, obviously, and he’s also trying to take the place that Blaine had as the leader of the Warblers [his school’s show choir].”

The two halves of Glee’s only on-screen gay couple, excruciatingly referred to in some quarters as ‘Klaine’, were going to be shown not just to be “together because they’re the only two gay characters”.

Now, in an interview with E!, Gustin says: “At first, first people were like, ‘Oh this guy’s cool, we like him, blah blah blah’. Then they found out what the character was going to be.

“And then all these pictures started coming out of, like, Darren Criss and Chris Colfer with my headshot in the middle.”

He continues: “Right off the bat, before people had even seen an episode – I don’t know, I never took these too seriously – literally death threats on Twitter, saying ‘If you break up Klaine, I will find you and I will kill you’.”

Gustin laughed off the threats and went on to praise the “intensity” of Glee fans in general.

The show is gearing up to feature another gay couple, with Jeff Goldblum set to pair up with Brian Stokes Mitchell as they play character Rachel Berry’s parents.

The Jurassic Park actor and Broadway star Stokes will sing a duet together during their début in a special Valentines Day episode called ‘Heart.’