“I played for Real Madrid, but I was also the world's No. 1 Call of Duty player”

The engimatic figure of Thomas Gravesen has been full of surprises throughout his footballing career, from arriving at Real Madrid at the peak of his powers to leaving his Celtic teammates in awe of his skills in the pool.

But perhaps the Dane's most impressive achievement off the football field came as a result of his obsession with video games, during which he apparently became one of the world's best Call of Duty players.

Gravesen's career did not follow the typical path of a Premier League footballer in the mid-2000s, having joined Everton from then-Bundesliga club Hamburg in 2000.

The Dane's tough and tough nature earned him the nickname “Mad Dog.” It also gave him a key role in David Moyes' setup at Goodison Park, where he racked up 155 appearances and scored 11 goals in five seasons.

But when he turned 27, he decided to try his hand at playing in Spain after Madrid – then managed by Vanderlei Luxemburgo – were wowed by his set-piece abilities, including his trademark long touch.

The La Liga giants managed to sign him in a surprise £2.5million deal in January 2005, with his contract due to expire in the summer. But after spending just 18 months in the Spanish capital, he transferred to Celtic in the summer of 2006.

This is where Gravensen's unconventional lifestyle off the field really showed, as his teammates discovered his bizarre lifestyle habits.

His former Hoops teammate Paul Caddis revealed Gravesen would return to his parents in his native Denmark to play video games instead of going on a pre-season holiday with his Celtic colleagues.

“He was coming back [to Denmark] in pre-season and stay either with his mother or his father [house] in an attic, probably the size of a full table,” Caddis said, appearing on the Undr The Cosh podcast.

“In this little attic, a tiny room for six weeks, [he] he was just sitting on his PlayStation. He was like number one or number two in Call of Duty at one point.”

Gravesen also entertained his teammates by challenging them at the pool table and it was claimed he even played with a cue signed by seven-time world champion Ronnie O'Sullivan.

“He brought us all, all the young guys, [and say] “Twenty-five pounds a head,” Caddis added.

“He only played for money and we never knew why. He would say 'everyone put their money in'. Before it was like £250 sitting in there. 'Two minutes guys'.

“And he was running down the stairs at Celtic Park. We were looking out the window, he was opening his boot and he was pulling out this fucking Ronnie O'Sullivan pool cue, snooker cue, all fucked up.

After retiring from football in 2008, Gravesen claims to have earned £100 million after making shrewd investments with his football earnings. He even lived in Las Vegas at one point, with Nicolas Cage and Andre Agassi among his neighbors in a gated community.

He now resides with his model girlfriend Kamila Persse in Denmark. But don't be surprised if you come across the 48-year-old dominating late in a game of Warzone.