'Saturday Night Takeaway' presenters Ant and Dec have revealed that reuniting as PJ & Duncan happened because they had a little time slot left to fill on their weekend entertainment show.

Their single, 'Let's Get Ready To Rhumble', is now on course to be this week's No.1 and the pair told ITV's 'Daybreak' that it was just a joke that blew way out of proportion and really surprised them:

"It was just a joke. We were fans of 'The Big Reunion' anyway, so we were going to do something with them at the end of the show. And then we realised we didn't kind of have enough to fill what the end of the show normally runs to."

"And we thought well, we could possibly dust the old baseball caps off and give it a go for a laugh. And the production team on 'Saturday Night Takeaway' went mad, saying, 'We remember that song, let's do it!' So we thought it would be a bit of a laugh then, we'll do it. We never expected we would be No.1 in the midweek charts."

Watch the duo perform their rendition of 'Let's Get Ready To Rhumble' here: