Jared Leto's Joker left cast and crew in awe

Jared Leto was so "fascinating" as comic book villain The Joker he literally stopped his Suicide Squad castmates in their tracks as he appeared on set.

Director David Ayer admits the Oscar winner was so captivating in character, work on the comic book adaptation was briefly halted as everyone paused to take in Jared's appearance when he first showed up in costume.

"When he steps onto the set the world stops. Everything stops," Ayer told Total Film magazine. "What Jared has done is absolutely incredible. What he's done is so powerful, so menacing, so palpable, you can feel him.

"The crew stops working and just watches him. I have to get everybody going again because he's so fascinating."

Leto fully embraced his role as the Joker, refusing to break character in between shoots, but he recently revealed the method acting experience left him feeling pretty lonely.

"There was definitely a period of... detachment," he told Entertainment Weekly magazine in October (15). "I took a pretty deep dive. But this was a unique opportunity and I couldn't imagine doing it another way. It was fun, playing those psychological games."

Leto went on to compare the whole process to "giving birth out of my prick hole".

He even sent his co-stars unusual gifts to help him get into character before joining the rest of the cast for filming.

"He sent (Margot Robbie) a nice love letter with a black box with a rat in it - a live rat," co-star Adam Beach, who portrays Slipknot, told E! News last spring (15). "It was beautiful. Then he sent bullets to Will (Smith) with a letter."

Margot Robbie, who plays Harley Quinn, subsequently admitted she was initially caught off guard by the odd present, but she understood the thinking behind Leto's rodent gift, which she named Rat Rat.

"If Harley got something from Joker, she'd probably cherish it," the Australian beauty explained to Elle magazine of her decision to keep the rat. However, she has since revealed Rat Rat has found a new home with director Guillermo Del Toro, as Robbie's landlord objected to her choice of house guest.

Suicide Squad, which also features Viola Davis, Joel Kinnaman, Jai Courtney, and Cara Delevingne, opens in cinemas in August (16).