These are the best pranks pulled on the set of Game of Thrones

While the rest of us sit around theorising over what will happen next on Game of Thrones, the show's creators are having fun with the unknown.

Because they (and George RR Martin, of course) are the only ones who know what's coming next at any given time, show runners David Benioff and Dan Weiss have used the opportunity to prank the cast over the years.

They revealed a few of the best pranks they've ever pulled to Entertainment Weekly, and they hit everyone from Ygritte to Sam to Jon Snow himself.

Jon Snow's beautiful, beautiful hair

Jon Snow and his luscious locks. Photo / HBO

There was a scene in which Snow sets a white walker on fire while defending Lord Commander Mormont, but Kit Harington was sent a different script.

It read: "Jon plunges his hand into the fire, seizes the burning drapes, and flings them at the dead man, engulfing them both in flames".

"When the fire is finally out, we see by torchlight that all of Jon's hair has burnt down to the scalp. The skin on the top half of his face has been melted in the extreme heat, blistered and pustulant. Despite what must be the extreme agony of permanent disfigurement, Jon stands stoically by his master's side."

Then Mormont says to Jon: "Gods, boy. I was wrong about you. You're a ranger, through and through."

It ends: "Jon smiles, his teeth shining brightly in his destroyed face. Mormont, sickened, has to look away."

When Harington arrived on set, they explained that HBO had concerns the Jon Snow storyline was "too Harry Potter" and wanted to make it darker.

"We kept this up until we started laughing. He was a remarkably good sport about the whole thing."

Bran kills Theon

Alfie Allen as Theon Greyjoy. Photo / Supplied

The second season ended with Theon Greyjoy losing control of Winterfell, and Alfie Allen (Theon) didn't know if his character would return for season three.

He got sent a prank script in which Bran Stark said to Theon, "This is my Winterfell, not yours" and proceeded to stab him in the heart.

The awkward bit was Allen bought it.

"I thought it was cool...I went on a holiday, and David and Dan were all thinking I was going to call up going, 'Hold on a minute whoa-whoa-whoa!' But I just got on with it. Then they had to make it clear to me later on it was all a joke," he said.

John Bradley suits up

Kit Harington (Jon Snow) and Hannah Murray (Gilly) were behind this one.

They asked the showrunners to help them prank John Bradley (Samwell Tarley) with a bogus costume.

He was brought in for a mock fitting with this "ludicrous" costume which was "just believable enough to not know it was a gag".

Bradley said: "I looked so bad and ridiculous, it was unbelievable...There was a huge vulgar codpiece - though flattering, to be sure.

"The reason I bought it is because we'd never seen Sam at home before, and [his parents think] he's an idiot. [Maybe] Sam dressed like an idiot before he came to Castle Black".

Rose Leslie: future pop star?

Rose Leslie as Ygritte. Photo / Supplied

The show runners learned Leslie (Ygritte) hated the idea of singing in public. "

"There's a song in the books that Ygritte sings, The Last of the Giants" Benioff said.

"The earnest song by Thrones author George R.R. Martin is 20 lines long and contains lyrics such as 'Oh I am the last of the giants, so learn well the words of my song, or when I am gone the singing will fade, and the silence shall last long and long.'"

They sent her a fake script in which a scene required her to sing the entire song on screen.

Jaime Lannister turns the tables

Nikolaj Coster-Waldau as Jaime Lannister. Photo / Supplied

Nikolaj Coster-Waldau (Jaime Lannister) pranked the show runners after learning his character was to get a hair cut.

He wrote an "angry actor email" about how upset he was over the change.

"He said he felt the need to own his hair because his hair was part of his character, and he was going to take it upon himself to get his own haircut that he felt best reflected Jaime Lannister as he saw him," Weiss recalls.

He later sent them a photo of himself with all his hair shaved off, which was a problem because they were organising re-shoots and the footage wouldn't match.

"HBO's lawyers were calling his lawyers," said Weiss, but then Coster-Waldau came clean saying the photo was actually five years old.

Well played, Ser Jaime. Well played.