In a sneak peek from Saturday night’s show, the comedian could be seen leaving the orange sofa as he declared he was going to have “a nosey around”.
As he walked towards the skyline, which forms the backdrop to Jonathan’s set, the presenter began to panic.
And he was right to do so as Peter could be seen climbing through a square in the grid and leaving the studio.
Stunned by the events taking place, Jonathan exclaimed: “Oh, you see that’s not meant to happen.
“That’s a health and safety issue. You’re not allowed to do that!”
But Peter ignored Jonathan’s warning and began to clamber up the set before taking down parts of the London skyline and rearranging them.
The 44-year-old’s disruptive behaviour didn’t end there either as he went on to climb on Jonathan’s desk before inviting members of the audience on set.
Peter explained to the host that he had offered him up as a raffle prize at a recent Christmas Fayre: “I basically offered you as a meet and greet. They’re here.”
He then called competition winners Mary, Anne and Philip on stage where they joined him on the sofa to meet Jonathan.
Peter then guided the trio into the green room where they met with his fellow guests Luke Evans, Sheridan Smith and Iain Stirling.
The Jonathan Ross Show airs Saturday on ITV at 9.40pm.