The ratings came during a question and answer game with Corden, where the alternative to answering was to consume a questionable snack.
The Late Late Show host asked the 32-year-old pop star to rank her exes from best to worst in bed, "working on the notion that they're all good."
Perry protested vehemently at first: "They're all amazing lovers and I would have sex with all of them after I get out of this place!" she told Corden.
Eventually. her final ranking listed Diplo, whom she dated briefly in 2014, at the bottom, followed by recent ex-boyfriend Orlando Bloom, with John Mayer -- with whom she had an on-and-off relationship that ended in 2015 -- at the top.
But there was one more man worth mentioning: Josh Groban, whom Perry referred to as "the one that got away," after they were linked together in 2009.
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Perry inhabited a Big Brother-style house for the duration of the livestream, opening her life up to the public for 72-hours,which included an emotional therapy session.