'Til death do them part: Bono believes unshakable U2 will stay together until they die

They have already been together for a whopping 35 years, but U2 frontman Bono has reassured fans that the rock band will not be splitting up any time soon.

The 51-year-old insisted that he believes they will keep making music until they die, because they are so defined by their roles in the band that they are otherwise 'unemployable'.

He was speaking at the Toronto Film Festival, where he is with guitarist The Edge to launch documentary From The Sky Down about the making of their 20-year-old album Achtung Baby.

Strong Bond: Bono says U2 will never split up

Bono said: 'We're unemployable, you know, it's like the priesthood. There's only one way out, in a coffin.'

He also added that the Irish group, which has won a record-breaking 22 Grammy awards, have 'a kind of belligerent respect' for each other which unites them.

The film centres on the making of the album in Berlin, which helped the band's reinvention, and is directed by Davis Guggenheim.

Boys on film: Bono and guitarist The Edge (R) pose with director David Guggenheim at the launch of U2 documentary From The Sky Down

And the singer admitted that watching the film had been difficult, because he wants to focus on the future instead of the past.

He said: 'I found it very hard to watch to be honest with you. We're not very good at looking back at things. I mean Edge - when he put together our Best Of collections - forced me, actually had to physically force me, to listen to it before it went out.

'I'm just not interested in what we've done, I'm always more interested in what we're about to do. But you know, for this album, we made an exception.'

Modest: Bono admitted he could not see the appeal of the documentary

Photo op: An eager fans takes a photo of herself with Bono

While he turned up at the gala screening and happily took photos with and signed autographs for fans, Bono confessed that he does not see why people would find the film appealing.

He said: 'It's like a load of songs and they turned out pretty good in the end, and this is a film about how they nearly didn't. I don't know why anyone would watch it, I really don't.'

But The Edge, 50,whose real name is Dave Evans, seemed to have a better grasp of it.

35 years in the business: L-R Larry Mullen Jr., The Edge, Bono and Adam Clayton

He explained: 'I think it's not a movie about us, per se, it's really about how bands function, or in this case, don't function.'

The boys shed their rock'n'roll image last week and sported suits to the GQ Men of the Year Awards in London.

The band, whose other members are Adam Clayton and Larry Mullen Jr., formed as teenagers and have since sold more than 150 million records worldwide.

They are still as strong as ever and headlined Glastonbury festival earlier this year.

Scrubbing up: Adam Clayton, The Edge and Bono attended the GQ Men of the Year Awards last week

Posted in: world stars