Game of Thrones' Joffrey Baratheon star looks unrecognisable as he bags new role in rebooted classic

However, his latest role couldn't be further from the fictional world of Westeros.

Gleeson will take on the part of Wentworth in upcoming reboot of classic tale, The Famous Five.

He's not the only star to be announced for the series as Diaana Babnicova, Elliott Rose, Kit Rakusen and Flora Jacoby Richardson have been cast as the titular group.

Babnicova will take on the role of George while Rose will play Julian, Rakusen will portray Dick and Richardson will bring Anne to life.

Of course, no Famous Five reboot would be complete without canine companion Timmy, who'll be played by Bearded Collie Cross, Kip.

Elsewhere in the cast, I May Destroy You's Ann Akinjirin will play Fanny while Ted Lasso's James Lance will take on the part of Quentin.

The upcoming show's director and executive producer Tim Kirkby said of the series and cast announcement: "Our brilliant young cast are mind-blowingly talented and, along with Kip, they are already bringing these gorgeous characters to life in a fresh and modern way.

"Together with the brilliant Jack, Ann, James and Diana [Quick] we can’t wait to bring these glorious, action-filled, epic, family adventures to the screen."

Filming for the BBC series takes place across the South West of the UK and a release date remains to be seen.

While Gleeson's GOT character was synonymous with striking blonde looks and boyish facial features, it's safe to say Wentworth is the polar opposite.

Gleeson has instead opted for a jet black barnet for the role, complete with a bushy moustache.

Long gone are the days of Lannister armour as Gleeson's days on set will now be spent in pin-striped suits and eye-catching bling.

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After leaving Game of Thrones, Gleeson took a six-year hiatus from the world of on-screen acting after initially announcing his retirement.

He made a return to the small screen in 2020 in a few episodes of Out of Her Mind and a year later, appeared in movie Rebecca's Boyfriend.

After exiting GOT, he spoke out about his decision to step away, telling Entertainment Weekly: "The answer isn’t interesting or long-winded.

"I’ve been acting since age eight. I just stopped enjoying it as much as I used to.

"And now there’s the prospect of doing it for a living, whereas up until now it was always something I did for recreation with my friends, or in the summer for some fun.

"I enjoyed it. When you make a living from something, it changes your relationship with it.

"It’s not like I hate it, it’s just not what I want to do."