Shocking moment MAFS UK star Kieran kisses another bride as wife Kristina breaks down in tears

A first look at tonight's instalment of Married At First Sight UK has set thousands of fans' tongues wagging, after it looks as though one formerly loved-up groom locks lips with a bride that isn't his own.

In a video which has since gone viral online, fan-favourite Kieran Chapman - who was paired up with wife Kristina Goodsell when the series kicked off last month - is seen dropping a kiss onto the lips of another contestant.

The couple have enjoyed a natural progression of their relationship so far (Channel 4)

Kieran and Kristina have enjoyed a pretty smooth-sailing journey on the hit Channel 4 dating series so far.

Seconds before tying the knot when the series began in September, mechanic Kieran had his future other-half in stitches after pulling a prank on her by wearing a set of rotten false teeth as she approached him down the aisle.

Kristina's light-hearted reaction was a sign of what was to come for the couple, whose relationship has gone from strength to strength in recent weeks.

Though the pair did hit several bumps in the road last week.

One episode saw Kieran express his concern over his wife's PMDD, after which viewers praised him for supporting her through it and vowing to give their marriage all he could.

And after this year's stars were introduced to one another's in-laws, further cracks began to show between the pair.

Naturally, therefore, fans of MAFS have been left further horrified today after a preview for tonight's episode (24 October) seemingly shows Kieran getting lipsy with another bride during a group dinner party. Take a look:

In a controversial clip, which has since accumulated thousands of views online, the groom could be seen leaning down to kiss his co-star Polly - who herself is paired up with husband Adam Valentine - on the lips.

And while the peck seemed to have been in jest - with Kieran, Polly and Adam laughing it off - Kristina appeared far from amused when the camera panned over to her.

"Did you just kiss another wife?" she demands to know.

Later, breaking down before her fellow brides, Kristina confessed: "I'm gutted."

Elsewhere in the teaser, viewers saw Emma Barnes and her hubby Caspar Todd once again come to blows over their ongoing intimacy dispute.

Faces cracked when Caspar accused his bride of wanting to 'test out having sex' with him.

And on top of that, a surprise arrival from a mystery guest is guaranteed to leave fans further blindsided.