David Harper, 52, has been on Antiques Road Trip since it first began on the BBC back in 2012 and has seen many celebrities participate in the special episodes.
But the antiques star revealed not everything goes smoothly and they regularly experience huge losses on the BBC One show.
David said it is especially worse when a celebrity is on the programme as he explained when a loss occurs, the stars want to “get away” as quickly as possible.
Speaking to Express.co.uk about mistakes on Antiques Road Trip, David revealed: “Losses and disaster in auction are the worst.”
He continued: “When we are filming these shows, you can be as knowledgeable and animated about an object as you would like.
“But once you take it to an auction, and it’s just a cold loss, that’s hard.”
He added: “Sometimes they couldn’t give a monkey about the object, it can all go badly wrong.”
Revealing why it’s worse when a famous guest star is on board, David divulged: “Especially when you’re with a celebrity, it doesn’t always go to plan.
“You’re meant to be an expert, and when it all goes badly wrong, they look at you like you have got some sort of lurgy and they want to get away from you as quickly as possible.”
David, who will be sharing more stories from his career during his theatre tour, Unexpected Tales Tour, also revealed a celebrity guest almost got them both arrested.
He explained he had been filming with a star, who he didn’t want to name, when the person in question began flashing their bottom to onlookers
“We were filming and he had just been awarded rear of the year, which if you know who this character is, this got him very excited,” he began to spill.
“So he couldn’t stop talking about it and then he started showing his rear.”
The BBC One favourite said: “Luckily he kept his underpants on which were very skimpy and a bit shocking!”
David went on: “He was showing his rear so much, things developed and we almost got arrested!
“The police got involved, public complaints were involved and indecent exposure was involved.”
David will be spilling more and potentially identifying celebrities during his Unexpected Tales Tour.
Revealing what the shows will entail, he said: “It will include stories behind the camera and stories I shouldn’t be telling anyone!
“So I hope no-one from the BBC is there!”
Antiques Road Trip airs today on BBC Two at 5.15pm.
To buy tickets for David Harper’s tour, click here.