The Oscar-winning actress revealed she accidentally sedated herself before filming a scene for the blockbuster film franchise, on Monday's (23May16) The Tonight Show Starring Jimmy Fallon.

During a game of True Confessions, the 25-year-old actress, who rose to fame as heroine Katniss Everdeen, had to tell a story and host Fallon and fellow guest, English comedian and host of Last Week Tonight, John Oliver, had to work out if Jennifer was telling the truth or a lie.

Jennifer then told Fallon: "I once took an Ambien before filming a scene in The Hunger Games." Ambien is a sedative typically taken by people with insomnia.

"Were you sleeping in this scene?" Fallon inquired before Jennifer confirmed, "No, in fact, I was dancing." And after Oliver asked if she took the sedative before a fight scene, the actress explained, "I woke up and I thought it was something else, it was like normal to take it."

When their time was up, Fallon and Oliver said they believed she was telling the truth with the Last Week Tonight host saying, "It's plausible, it's reckless, I kind of like it, if it's not true I'm going to be very sad."

A shamefaced Jennifer revealed she did in fact take the drug, mistaking it for something else.

During her interview with Fallon, Jennifer revealed she was forced to undergo media training after one of her first media events was a disaster.

As a teenager at a press conference for 2008 film The Burning Plain, which also starred Kim Basinger, the X Men: Apocalypse star was asked by a reporter, "Where is Kim Basinger?", and she replied: ''You didn't hear? Kim died.''

"I was ripped off the stage and thrown into media training," laughed Jennifer. "Obviously it didn't take."