UFC fighter Diego Sanchez was left furious after he was kissed by British fighter Craig White.
The 28-year-old from Devon planted a smacker on the nose of his upcoming opponent at the pre-fight weigh-in.
The pair, who go head-to-head in Texas on 8 September, had to be kept apart by UFC owner Dana White.
The main event at UFC 228 will be a Championship fight between Liverpool's Darren Till and the American Tyron Woodley.
The pre-fight weigh-in is usually a fighter's final chance to leave a psychological mark on an opponent before inflicting a physical one.
Exmouth-based fighter Craig "The Thundercat" White is a grappling specialist, so fans are used to seeing him perform an arm bar or choke hold.
But the crowd was shocked when the 28-year-old pulled off the unusual move of kissing his rival.
After hopping off the scales and posing for the obligatory nose-to-nose trash-talking pictures the 28-year-old pressed his lips against Diego Sanchez's nose.
The two welterweights will face off on the undercard of UFC 228 at the American Airlines Center in Dallas, Texas.
The night will be headlined by another British welterweight, Liverpool's Darren Till - who'll fight Tyron Woodley for the championship belt.
If Till manages to bring the title belt back to the UK it'll be the latest chapter in an incredible career.
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#Repost @santamaluco with @get_repost ・・・ In honour of our co-owner Darren Till challenging for the UFC World Welterweight Championship this Saturday night/Sunday morning in Dallas, we will be staying open to the small hours to show the main event live at his restaurant Santa Maluco on Castle Street. Santa Maluco will become the official fan zone for one night only!! The fight is due to start around 4am local time but we would advise it best to get there early. We will be serving pizza by the slice and all of our usual drink offerings will be available.🍕🍷🥊🤼🏽♂️
Before competing in the UFC he specialised as a Muay Thai kickboxer.
But he learned other martial arts disciplines in Brazil - he was sent there after being stabbed in a Liverpool nightclub aged 19.
His coach booked a one-way flight saying he wanted to help the teenager escape the distractions of home.
Darren Till spent almost four years in the South American country perfecting his craft.
A win in Texas would see the the Liverpudlian become only the second Briton in history to claim UFC gold.