'I am gonna kill you' furious Simon Cowell warns Ant and Dec in rant ...

SIMON Cowell aimed a furious rant at Ant and Dec after they managed to prank him for a SECOND time on Saturday Night Takeaway.

The comedy duo kicked off their 20th and final series by reminiscing on some of their favourite moments of the show.

Ant & Dec kicked off the final series of Saturday Night Takeaway this eveningCredit: ITV The duo pranked Simon Cowell again for their Undercover segmentCredit: ITV He was left furious with the two jokestersCredit: ITV

The nostalgic pair brought up their first ever Undercover escapade where they pranked Simon Cowell live on American Idol.

Ant and Dec decided to come full circle by catching him out again two decades later.

The cheeky show hosts headed out to Los Angeles to target the TV personality once more.

For their first prank, they paid two actors to dress as cops and stop Simon on his regular bike ride through Malibu.

The phony police officer gave the celeb a dressing down for not wearing a helmet or any reflective clothing - despite it being the middle of the day.

He then told Simon that his bike was not in the 'regulation colours' and if he did not repaint it he would be banned from using the two wheeler in a matter of days.

The BGT judge was then forced to wear a tacky yellow hi-vis vest for the remainder of his cycle.

The fun didn't stop there, as Ant and Dec decided to wind him up further by pranking him live on America's Got Talent.

They hired a fake magician who locked Simon in a metal box and chained him up, before pretending to swallow the keys.

Backstage Ant and Dec descended into a fit of giggles as Simon got progressively angrier when they announced that the keys had gotten stuck in the performer's throat.

AGT stage crew members joined in the ruse, pretending to try and cut Simon free with a chainsaw.

Just when they were about to use explosives to blow up the metal box he was stuck in, Ant and Dec took to the stage and revealed they had organised the whole incident.

A fuming Simon Cowell exclaimed: "I am going to kill you!"

While still trapped in a headlock, the helpless judge added: "You are in so much trouble."

Ant and Dec took no notice of him, gleefully announcing to the American audience that this escapade was part of their Undercover segment for British Saturday Night Takeaway.

Viewers were left in fits of laughter at the prank, with one writing: "Simon Cowell locked in a box on stage in front of all those people was better than the first prank on him all those years ago. Well done, lads."

Another added: "No cos I’m actually crying at that Simon Cowell prank on ant n dec."