The Prison Break revival has brought the old gang back together – with one notable absence.

William Fichtner won't be reprising his role of Alexander Mahone, instead signing up as a series regular on sitcom Mom.

So why was Fichtner left off the call sheet? Robert Knepper – who plays T-Bag on Prison Break – has revealed that writer Paul Scheuring made the decision to omit Mahone.

"I really trust Paul Scheuring – and Paul loves Bill Fichtner and I love Bill Fichtner," Knepper told press including Digital Spy at San Diego Comic-Con.

"He's a brilliant actor – but Paul honestly said to me, 'I don't know what to do with that character'.

"He didn't want to just bring everybody back, so that the audience go, 'Oh, look, it's Bill Fichtner again!' – he honestly thought, 'I'm not sure where to do that in the plot'.

william fichtner as mahone in prison breakpinterest
Everett / REX//20th Century Studios

"So if someday there's another chapter of this, maybe then Bill will be back. But I think the characters that are there, each of our moments that we have, are key to the storytelling, which is how it should be."

So there you have it – though surely there's more to do with the complex, troubled ex-agent Mahone?

Here's hoping that Prison Break does come back for another go-around and we get to catch up with Mahone in the sequel...

Prison Break season 5: Cast, characters, plot and everything else you need to know about the reboot

See Wentworth Miller back in action in the first full scene from Prison Break right here:

preview for Michael Scofield is back in a new Prison Break extended clip