Prince Harry wore Tom Hardy's 'Mad Max' costume for his and Meghan Markle's last night of freedom before their relationship was made public

• Prince Harry borrowed Tom Hardy's "Mad Max" costume on a night out with Meghan Markle.
• He wrote in his new memoir, "Spare," that the costume made him "unrecognizable."

For his last night of freedom before his relationship with Meghan Markle was confirmed to the world, Prince Harry says he borrowed actor Tom Hardy's costume from "Mad Max" for a Halloween party in Toronto.

In the Duke of Sussex's new memoir, "Spare," Prince Harry detailed how he ended up "unrecognizable" on a night out before his quiet romance with Meghan became public knowledge.

Harry wrote that the couple, along with Princess Eugenie and her husband Jack Brooksbank, attended an "apocalypse" themed party at Toronto's Soho House for Halloween in 2016. Harry wrote that he had "not had great luck with themed fancy-dress parties, but I'd give it another go."

He said he phoned a friend for help with his disguise: Hardy, who played the titular role in 2015's "Mad Max."

"The whole thing?" Harry said Hardy asked him. "Yes, please, mate! The whole kit," Harry told his friend.

"He'd given it all to me before I left Britain, and now I tried it on in Meg's little bathroom," Harry wrote. "When I came out, she roared with laughter."

Harry said his costume was "funny and a little scary."

"But the main thing was: I was unrecognizable," Harry said. He added that Meghan wore "torn black shorts, a camo top, fishnet stockings."

When they walked through the party, Harry said, heads turned toward Meghan, whose costume didn't disguise her quite as well as her then-boyfriend, "but no one looked twice at her dystopian date."

"I wished I could wear this disguise every day," Harry said. "I wished I could reuse it the next day and visit her on the set of 'Suits.'"

Harry wrote that the party, their final outing in disguise, was "loud, dark, drunk — ideal," noting that they had been "tipped" off that "another apocalypse might be coming" the next day, when "everything was changed forever."

By the time he got to London, he said the story had "fizzled," because it was "all unconfirmed, and there were no photos, so there was nothing to fuel it."

"Maybe, I thought, all will be well," Harry wrote. "Nah. Calm before the shit storm."

Rumors had started swirling in October 2016 that Meghan and Harry were dating, but it wasn't until November 2016 that the Royal Family publicly confirmed the relationship.

The announcement came through a statement from the Royal's communications secretary on November 8, 2016, in which Prince Harry confirmed the relationship and criticized a "wave of abuse and harassment" Meghan had faced since reports of their dating started to circulate.