Amarah Maddar, 26, was walking past Millers pub in Kings Cross, London, on March 14 when she captured the questionable culinary practice on camera.
The man in question was socialising with five friends who “didn’t even bat an eyelid” when he dipped his pizza.
Amarah, a personal assistant from London, posted it on social media with the caption: “What have I just witnessed? Dipping Domino’s into your pint is criminal!”
The video quickly went viral and has racked up 140,000 views.
Most people were horrified by the practice, but some have come out in support of the pizza dipper.
One person hilariously suggested the ‘perpetrator’ be investigated by the Metropolitan police, posting: ‘Hello @MetPoliceuk Can you look into this please?’
Another added: ‘Not any pint, Guinness (crying face emoji)’.
Meanwhile one person defended the move: ‘He’s an innovator, leave him be’.
And some people argued it isn’t as bad as putting pineapple on pizza.
Amarah said: “I was walking with some colleagues to go and meet some friends for drinks after work.
“I passed the busy pub with people drinking outside and spotted a group eating pizza and drinking.
“My friends and I couldn’t believe it, it was such an odd thing to do we were all laughing at him.
“The friends we were meeting with wouldn’t have believed us to I took a video on my phone to show them.
“The guys friends acted like it was normal for him to dip pizza in his pint, they didn’t bat an eyelid.”
Amarah said that pubgoers were “just as horrified” as she was despite his friends not seeming to care.
She said: “People inside the pub spotted him dipping his slice in his pint through the window and they were just as horrified as I was.”