As reported by the Guardian, Neil Fingleton, 36, passed away on Saturday after suffering heart failure. The actor played Mag the Mighty on the popular HBO series “Game of Thrones,” and at 7' 7" was known as the U.K.’s tallest man. The Telegraph quotes Fingleton’s agent as calling him a “gentle giant.”

Fingleton wasn’t always an actor, as, with his incredible height, he started out as a professional basketball player. However, he then set his sights to acting and most recently starred in “Game of Thrones,” where he played the role of a giant in Mance Rayder’s Wilding army.

His character finally met his fate when storming the tunnel below Castle Black in the sixth season of the series.

Neil Singleton played several different roles

Mag the Mighty in “Game of Thrones” wasn’t his only role, however, as Fingleton also played the role of the Fisher King in the popular “Doctor Who” sci-fi series. He also, reportedly, starred in the 2011 film “X-men: First Class” as the Russian General's Bodyguard 1 and alongside Keanu Reeves in “47 Ronin,” a sci-fi fantasy/drama, back in 2013.

Mag and Mighty and Fingleton’s costume

The Telegraph reports that Fingleton explained how he became the fearsome Mag the Mighty, saying that to create his costume, he had to have a full body cast fitted.

He reportedly asked the interviewer to picture having an arm in a cast, then said to imagine what it would be like to be encased from head to toe in plaster. He said it was necessary, in order to get the exact shape and dimensions of his body to create a costume to fit him perfectly. Reportedly the costume itself was pretty heavy too.

He also needed long hair and a beard for the role and it took four hours each morning to fit the prosthetics. This meant starting work at around 3 a.m. to be ready for shooting the latest episode at 9 or 10 a.m.

On Sunday a notice was posted to the Tall Persons Club group on Facebook, speaking of his death.

The Facebook post noted that Neil had become Britain’s Tallest Man in 2007 and the group passed their thoughts and condolences on to Fingleton’s family.

This latest news follows the death of Peter Vaughan, who played Maester Aemon in “Game of Thrones,” and who passed away in December last year at the age of 93.

Fingleton can be seen in action in the video included below.