First reported by The Daily Mail, Over the weekend Katy did an extensive YouTube live stream to promote her new album, Witness.
During the stream, James Corden, host of CBS's The Late Late Show, dropped by to chat with Katy and ultimately convinced her to divulge who was the best she ever had and who was the worst.
Starting at the bottom of the list, Katy said that her least favorite partner was DJ Diplo, who she dated briefly a few years ago.
The second place trophy went to her most recent beau, actor Orlando Bloom (The Lord of the Rings: The Fellowship of the Ring, Pirates of the Caribbean: Dead Men Tell No Tales).
Ultimately, though, Katy said, "They're all amazing lovers and I would have sex with all of them when I get out of this place!"
Not content with leaving the conversation at loves she's had, the conversation turned to loves she missed out on.
Katy told Corden that she felt like pop-opera singer Josh Groban was "the one that got away," and added, "He's one of my good friends. I love him so much. He's the best."