Married At First Sight Australia’s Mike Gunner accused of ‘cheating on Heidi’ during filming by co-star Cyrell Paule

MARRIED At First Sight Australia's Mike Gunner has been forced to deny allegations he was cheating on Heidi Latcham while they were 'married' on the hit show.

His co-star Cyrell Paule has sensationally claimed Heidi discovered he'd been unfaithful during filming - but Mike has slammed the accusation as "nonsense".

Cyrell, 32, has thrown allegations at Mike after the pair fell out when he blocked her on Instagram.

In an exclusive interview with The Sun, Cyrell said: "I know for a fact he was cheating on Heidi with another girl while they were filming.

"Heidi is a good friend of mine and she admitted that to me.

"When he was talking to the guys and saying 'oh it just didn't work out, but she's a lovely girl', I thought - 'Don't talk out of your f***ing arse, you lying piece of s***, you were f***ing another b***** while you were filming.

"That's what I said to him and that's why he hates me. "I'm brutally honest, I don't care. I had to call him out.

"It's no loss to me that Mike Gunner, some bald ass dude that wants to look like Jason Stantham stops talking to me.

"Big loss in my life, honestly...

"I swear to you I was nice to him the whole way through the experiment because I had no idea he was doing that. Heidi made me swear that I didn't tell anyone about the cheating."I hate b******* artists."

Mike is yet to respond to Cyrell's claims and Heidi has never spoken publicly about the allegations.

Married At First Sight viewers watched as Mike broke down in tears in the finale episode as he admitted he was still in love with Heidi - despite their marriage failing.

Heidi revealed Mike had broken her heart, as they explained to the show's matchmakers they had split because they "saw things differently".

Despite their relationship being over, the exes were very emotional as they reflected on what went wrong - and refused to rule out the chance of a reconciliation.

But since filming the heartfelt moment, Mike has gone public with his girlfriend Sonja.

He is now facing allegations of cheating during their relationship by his ex-pal Cyrell.

She says their feud first began when Mike was upset she didn't agree to appear on his podcast.

He promptly blocked her on Instagram and the pair came to blows while filming the grand reunion two years later.

Cyrell added: "Mike blocked me on Instagram before the reunion because I didn't want to go on his stupid podcast. 

"I don't even listen to podcast so why the f*** would I want to go on it.

"It never gets aired, but I said 'why are you saying hello when you unfriended me on Instagram'.

"You don't unfriend me then talk to me. He then hated me even more."

When The Sun reached out to Mike, he said Cyrell's allegations were "simply false".