The Avengers star Clark Gregg was stunned to receive an offer to lead a spin-off Tv show based around the superhero movie because his secret agent character appeared to die on screen.

The actor has played Agent Coulson in a number of Marvel films including two Iron Man installments and Thor, but his character seemed to meet an untimely end in 2012 blockbuster The Avengers.

Gregg is reprising the role for new Tv spin-off Agents Of S.H.l.E.L.D. and he admits he was surprised to receive an interesting phone call from The Avengers writer/director Joss Whedon after filming wrapped.

He says, "My next-to-last day on The Avengers involved this certain... fellow impaling me quite convincingly. I made jokes like, 'Is there a rewrite going to be coming from the governor at any point? Do you want to shoot one where he grazes me a little bit?' And there were a few pathetic answers... And it was really clear that I was dead... I didn't think I was going to be coming back from that...

"Four or five months after The Avengers, I got a call from Joss and we talked about how much we wanted to have whatever reason Coulson had for being alive and walking around, not be anything that undermined the reality of The Avengers. When he explained to me a little bit more... I hung up the phone very deeply on board."

Whedon has directed the pilot episode of the show, which is slated to air in the U.S. in September (13), but plot details are being kept tightly under wraps. He adds, "There was never going to be a show called Marvel's Agents of S.H.I.E.L.D. without Clark."

The moviemaker also refused to reveal whether any of The Avengers' big name superheroes will be making a cameo appearance in the Tv show: "We're still working that out... It's a fun opportunity (but) it's not the reason behind the show."