The iconic Saturday morning kids show was renowned for its innuendo and saucy jokes, which helped it appeal way beyond its intended audience of children.
However, when SM:TV first started in 1998, it fell flat, with Ant and Dec forced to take action to stop it being pulled off air.
Speaking on the upcoming documentary The Story Of SM:TV Live, which airs on Boxing Day and sees the pair reunite with co-host Cat Deeley, Ant said: “We are the presenters we are today because of that show.
“We learned how to do it there – and there’s no better breeding ground than Saturday morning television. But it wasn’t great for the first couple of months. There was no atmosphere. We got it wrong initially.
“People were putting pressure on ITV. Other production companies were saying, ‘Look, they’re not doing it ratings-wise, it’s not great. You should replace it with one of our shows’.”
Dec admitted the pair recognised they needed to change the show in order to save it, having ploughed their own money into setting up a production company to make it.
He recalled: “It had been going fairly badly for a long enough time that people were starting to ask questions. ‘Should this show be on air?’
“I thought, ‘If they pull this I’m gonna lose my house. I’ll have to go back to Newcastle and live with my parents again’. We were like, ‘Oh boy, this is bad!’”
Reflecting on the shake-up, Dec said: “That was always in the back of our mind when we were coming up with ideas – there was a bit for everybody.
“And it got to a point where it was not difficult to book the show because everybody wanted to come down.”
The Story Of SM:TV Live airs on Boxing Day at 9.25am on ITV.