20 best on-set practical jokes

The knitting ambush

The Prank: Even Tom Hanks can turn into a trickster given the right circumstances. On the set of his own movie, he found it hilarious that co-star Julia Roberts was obsessed with knitting, frequently taking to the hobby between takes. So he secretly had tons of knitting needles and wool ordered to the set and, when Roberts turned up for that days filming, she found the entire crew sat around trying to knit.

The prank backfired somewhat, however, when Roberts was delighted with the sight and proceeded to give lessons.

The shaving foam ordeal

The Prank: During a rare truce between the two, George Clooney and Brad Pitt decided to team up on the set of this film and ambush co-star Julia Roberts instead.

After escaping her hotel door covered in shaving foam, Roberts stormed down the corridor to Clooney's room only to meet a soaking wet porter along the way. He had just come from Clooney's room and fallen victim to the bucket of water balanced above the door that was waiting for Roberts.

The fake improvisation

The Prank: Producer Harvey Weinstein revealed the following practical joke played on Stellan Skarsgard when paying tribute to the late Robin Williams: Robin says to [director] Gus [Van Sant] and me: Let's welcome him to America. I'm going to change the script, and Gus, you tell him it's all about improvisation.

"So here's this scene about mathematic formulas, and Robin comes out and goes 'Jack Nicholson', and then he does Jack Nicholson. And then Gus, he's pointing to Stellan, and he's in a state of shock like a deer, and then he does Jack, and he does Bob DeNiro doing the scene, and he's like doing 15 things, and the crew is totally straight-faced while Gus is shooting. And then Stellan starts to ad lib this Swedish gibberish, because he's so lost in the scene. And then when Gus yells Cut, 180 members of the crew exploded with laughter, and Stellan looked around and goes What happened to me?'"

The tin stickers

The Prank: Clearly on-set practical jokes are no new phenomenon. Bert Lahr (The Cowardly Lion) and Jack Haley (The Tin Man) had quite the prank rivalry going on during filming of this fantasy classic.

The greatest joke of the bunch? While Haley was sleeping in costume, Lahr arranged for his Tin Man suit to be covered in tinned tomato stickers. This is the 30s equivalent of shaving off someones eyebrows.

The grave surprise

The Prank: While filming a scene in a Boston graveyard, Jennifer Lawrence felt particularly creeped out by the location... so co-stars Bradley Cooper and Christian Bale decided to wind her up.

They got the prop department to make up a gravestone with Jennifers name on it, which she spotted during filming and let out a massive scream. While still in hysterics, Cooper and Bale pointed out that they put down her date of death as April Fools Day.

The fart machine

The Prank: During a recent Reddit AMA, Daniel Radcliffe discussed a practical joke that was played on him: "Theres a shot in the great hall of all the kids sleeping in the great hall, and the camera starts very very wide, and comes in so that its an inch from my face.

"Alan Rickman decided he would plant one of those fart machines in my, uh, sleeping bag, and they waited until like the camera had come in for this huge DRAMATIC developing shot, and then unleashed this tremendous noise in the great hall."

The unforgettable theme

The Prank:In one of the films best scenes, the pretend family of Jason Sudeikis, Jennifer Aniston, Will Poulter and Emma Roberts travel in an RV and end up singing along to TLCs Waterfalls.

However, in filming the scene, Sudeikis and director Rawson Marshall decided to play a trick on their female lead and had the theme from Friends blast out of the speakers instead. Cue confusion followed by much eye-rolling.

The faked death

The Prank: Another example of Paul Newman being at odds with his director. When filmmaker Otto Preminger brutally rejected the actors script suggestions, Newman decided to get his own back.

During filming of a fight scene on a high platform, Newman started scrapping and then threw a dummy dressed in his same clothing off the edge, making it look as though Newman himself fell. Preminger reportedly collapsed following the scare and required medical attention.

The surprise flogging

The Prank: Footage of a joke played on Harrison Ford on the set of this movie only surfaced recently. It shows the actor filming a scene in which he is tied to a rock ready to be whipped.

The person whipping him, however, turns out to be none other than Barbara Streisand, who goads him about his Return Of The Jedi paycheque. Then, if that wasnt enough of a prank, his Star Wars co-star Carrie Fisher arrives on set to stop the whipping and rescue Ford.

The toilet fake-out

The Prank: Of the two leads in this film, you would think that Simon Pegg would be the prankster, but it seems that Thandie Newton is the one to watch, and with practical jokes that really are quite immature.

In a move that seems like something a young teenager would do on a school trip, Newton sneaked into Peggs trailer, mashed up a Mars bar into his toilet and left some dirty pants on the floor smeared with Marmite in the hope that the crew would see all this and blame it all on Pegg having a trouser accident.