A celebrity edition of the show aired on 10 July and featured Joe Marler, Lucy Pargeter and Sara Pascoe appear as contestants.
After Pargeter endured a rough start to the game, she joked: "[There was] someone with a magnet behind there flipping it that way."
Host Shephard responded by saying: "Don’t talk about the magnet. Conspiracy theorists love a magnet."
Pargeter agreed, joking: "I love a conspiracy theory."
A theory about the show's machine being manipulated by magnets has endured for years but Sunday's episode is the first time Shephard or the show have publicly addressed the theory.
After her initial struggles, Pargeter ended up making it to the final round with £3600 in her bank. However, she failed to take out the jackpot counter and when asked if she'd like to gamble for the £10,000 prize she elected to take the cash she had earned for her chosen charity.
Shephard recently paid tribute to a Tipping Point contestant that died after appearing on the show.
Cath, who filmed her episode of the show on 4 April, died later that month before it aired in May.
Shephard posted a picture of them on social media and wrote: "Today's Tipping Point is a poignant one… since recording the show, lovely contestant Cath, pictured backstage here, has passed away. Our thoughts and love are with her family and friends."
The official Tipping Point Twitter account also paid tribute to Cath: "After the recording of today's programme, we spoke with Cath’s family who shared the sad news of Cath's passing. Everyone at Tipping Point would like to extend their sincerest sympathies."
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