In addition to competing in the ring, McCallum was the owner of Pro Wrestling Elite and coached at Glasgow Pro Wrestling Asylum

Adrian McCallum, the professional British wrestler who went by “Lionheart” in the ring, has tragically died. He was 36.

The devastating news was confirmed in a tweet on Wednesday by Insane Championship Wrestling (ICW), the organization that McCallum formerly competed in and earned a 2018 World Heavyweight Champion title from.

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“We are heartbroken to learn of the tragic death of ICW World Heavyweight Champion, Adrian ‘Lionheart’ McCallum,” ICW wrote. “Adrian was a mainstay of ICW and British professional wrestling. Most importantly, he was our friend. His passing leaves a huge hole in the lives of those who knew him.”

Glasgow Pro Wrestling Asylum, one of Europe’s top professional wrestling academies that McCallum coached at, also issued a statement about his “tragic” passing on Twitter.

“We are heartbroken to learn of the tragic death of GPWA Coach Adrian ‘Lionheart’ McCallum,” the academy wrote. “Most importantly, he was our friend. His passing leaves a huge hole in the lives of those who knew him. Please respect his family & friend’s privacy at this time.”

At this time, it is unclear how the professional wrestler died.

In the hours before he died, McCallum shared a final tweet that referenced a quote from Ricky Gervais’ Netflix comedy After Life.

“‘One day you will eat your last meal, You will smell your last flower, you will hug your friend for the last time. You might not know it’s the last time, that’s why you must do everything you love with passion’ #Afterlife @rickygervais,” he wrote late Tuesday night.

McCallum’s passing sadly comes just a few days after he was renamed ICW’s World Heavyweight Champion and earned the title of Union of European Wrestling Alliances’ Heavyweight Champion.

The longtime athlete celebrated the accomplishment on his Instagram on Sunday and Monday, sharing two photos of his new golden title belts.

“‘The will of the strong will never be shaken by doubts of the weak…’‬ ‪#Champion #WorldClass” he captioned one of the photos.

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Prior to his weekend victory, the Scotland-based athlete, whose started his career in 2007, was a three-time Scottish Heavyweight Champion, and a three-time Preston City Wrestling Heavyweight Champion.

He also nabbed multiple titles in the Danish Pro, Premiere British, Real Deal, and One Pro wrestling leagues, according to Cagematch.

In addition to competing in the ring, McCallum was the owner of Pro Wrestling Elite, which puts on “high-caliber, action packed, family friendly shows.”

As news of his sudden passing broke, many people from the wrestling community shared their devastation on social media and said they would remember him for his lasting impact on the sport.

“Love you my brother. The Champ. RIP @LionheartUK – we will never ever forget you,” wrestler Grado wrote alongside a photo of the pair. “Thank you for everything you done for the British wrestling scene…but more importantly for being our pal x”

“Absolutely saddened to hear of the tragic loss of life of Adrian Lionheart McCallum,” wrote former ring announcer Tom Aitken. “We had our ups and downs in the wrestling business but it’s such a tragedy to hear of him die so young. A picture of happier times. RIP Hearto.”

“The passing of Adrian ‘Lionheart’ McCallum is so tragically sad. He was a great man who will be badly missed by so many of his friends and peers alike,” noted former British Heavyweight Wrestling champ Alex Shane. “His life’s work will (and should) be remembered by all on the UK scene – a scene that he truly helped to build. RIP Brother X”