Groom has explicit one-word response after making major mistake at wedding that left viewers cringing

A Married at First Sight groom made a mortifying mix-up at altar, leaving his new bride fuming.

The drama is coming thick and fast with the latest batch of hopeful singles hoping to find the love of their lives at the... altar.

The beloved reality TV show returned to Channel 4 for the ninth season of its UK iteration (it's also huge in Australia and the US, FYI).

The love gurus Paul C. Brunson, Mel Schilling, and Charlene Douglas decided which couples to 'lock in' and have meet for the very first time while getting married.

It seems they potentially made a mis-step when hooking up one couple, as the groom ended up complimenting the bride's twin - when he thought she was the one he was marrying.

Watch the clip here:

While marrying somebody the first time you meet them may sound extreme, dating apps don't seem to have a huge success rate, so it's no wonder people are willing to put on a white dress for a chance at love.

Viewers have been left totally dumbfounded upon last night's (17 September) episode which saw one groom leaving everybody cringing.

Nathan, 24, an engineer, stood at the altar waiting for his blushing bride.

He couldn't resist turning his neck when he heard footsteps coming down the aisle - and he loved what he saw.

"I can hear the heels," he remarked, before adding: "Wow."

When the woman in pink then sat down at a pew, he asked the guests: "Is that not her?"

Nathan and Lacey were married in last night's episode of MAFS (Channel 4)

To which he was informed: "No, it's her twin."

Non-identical, in case you were wondering.

Absolutely mortifying television - he fancies his bride's sister.

When the bride, 27-year-old Lacey arrived, all seemed to be going well and they exchanged vows.

Lacey then asked Nathan, in incredible scenes: "So is your type petite, brunette, big batty gal? Because I'm what you asked for."

Nathan replied with a reluctant: "Yeah."

Twin Paige was left feeling awkward (Channel 4)

Lacey didn't miss a beat when adding: "You hesitated there."

The bride was then informed that she looked 'nice', which added insult to injury.

Lacey said: "Nice? I want beautiful. I want gorgeous. I want stunning. Your nan looks nice. Your mum looks nice."

Lacey was then informed that her husband actually thought he was marrying her twin Paige.

She admitted: "It's not nice hearing that my husband is saying 'wow' to my twin. Growing up people used to say how my twin was prettier than me. That's annoyed me only because I didn't get a wow."

Nathan had viewers cringing (Channel 4)

Viewers immediately fled to social media to share their disbelief.

One person wrote on X: "I'm literally hiding at this cringe... he likes the twin .. producers are deep."

Another said: "Not the sister not the sister not the sister. Not her actual worst nightmare coming true. I feel sick!!!"

While a third added: "They did it on purpose having the twin walk in alone so he thought it was her. This is so awkward."

Married at First Sight airs every Monday to Thursday at 9pm on E4.