MAFS UK star Kieran makes sad four-word admission about relationship with Kristina as he kisses another bride

Married At First Sight UK star Kieran has made a sad four-word admission about his relationship with Kristina after last night's explosive dinner party.

It's been a really intense week for quite a few couples this week on the Channel 4 programme with Sacha and Ross clashing heads, Caspar and Emma dealing with yet another awkward moment and three sets of brides and grooms leaving the experiment after struggling to make it work.

It's been specifically emotional for fan-favourite duo Kieran and Kristina, with an earlier episode this week seeing the groom 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.

Last night's episode (24 October), however, took things to a whole new level after MAFS UK fans watched on as Kieran kissed another bride during a group dinner party.

He could be seen leaning down to kiss his co-star Polly - who herself is paired up with husband Adam - on the lips.

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

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

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

Kieran kissed Polly in front of his wife Kristina at the dinner party (Channel 4)

Kieran has since addressed the now-viral clip, taking to Instagram himself to share a series of four photos of him, Kristina and the other contestants at the dinner party.

He captioned the series of snaps with quite the teasing message.

"Did someone say 'let’s get f*cked up and have a dramatic dinner party?'" Kieran penned before he finally confessed: "I might have ACCIDENTALLY pecked another bride on the LIPS. #woops."

Cryptically, the reality TV star made sure to add: "@kristinagoodsell has the patience of a saint, and I’m super grateful for her."

Following the dinner-side drama, Kieran later opened up about where his head was truly at when it came to Kristina.

"I think she is incredible but..." he admitted before making a very sad four-word admission viewers at home no doubt will be upset by: "The spark is gone."

"It's just one of those things. She is amazing," he added.

Kristina was absolutely 'gutted' (Channel 4)

After watching the scenes, it's clear sofa critics back home couldn't wait to weigh-in on Kieran's bold admission which has seemingly come out of nowhere.

One X user questioned: "Can someone actually explain to me what has happened between Kieran and Kristina?

"He claims that the spark has gone or some sh*t but he was the one going full steam ahead originally. Then claims that he PMDD is also a contributing factor, I dunno something feels off."

"Kieran is such a typical player," declared a second. "He love bombed Kristina too hard and ran out of steam and now the piece of work is blaming his wife for it so he doesn’t lose his nice boy image."

Another piped up: "I knew the falseness between Kieran and Kristina would wear out at some point.. wasn’t really buying it."

And a final X user hit out: "If Kieran hurts Kristina I am NOT gonna be happy at all."

Married at First Sight UK airs every Monday to Thursday at 9.00pm on E4.