Katy Perry's dated some of showbusiness's biggest names names.

And now the I Kissed A Girl singer is kissing and telling - rating her lovers on their bedroom performance during her weekend longWitness World Wide livestream on Youtube.

Talking to James Corden, the 32-year-old revealed which of her exes was best in bed.

Truth teller: Katy Perry got real about the skills of her ex-lovers, ranking several from best to worst during her weekend of Witness World Wide livestreaming on Youtube

The Roar singer started her list from the bottom, naming DJ Diplo as her least favorite bedroom partner, after dating him briefly in 2014.

The California born starlet bestowed the silver medal named her most recent flame Orlando Bloom, who she split from in March.

John Mayer, who Katy was shared an on-and-off for relationship with for about three years, topped the star's lover list.

Lost love: Katy was outspoken on her relationships with John Mayer (left) and, more recently, Orlando Bloom (right)

Mortified! During the 32-year-old starlet's livecast, pal James Corden stopped by for some candid chat where he asked the Roar singer to rank exes Diplo, John Mayer and Orlando Bloom in bed

Not a tough question: Although she was mortified by the late night host's questions it didn't take long for Katy to answer, first ranking DJ Diplo at the bottom of the list

Although it didn't seem like Katy hadn't any trouble with her ranking, she admitted all of her exes are 'amazing' in bed.

A blushing Perry gushed to James, telling the late night host, ''They're all amazing lovers and I would have sex with all of them when I get out of this place!'

The Teenage Dream starlet also revealed one celeb she wishes she'd gotten in the sack, telling the English host she thinks singer Josh Groban is 'the one that got away,'

Silver medal lover? Number two was Katy's most recent ex Orlando Bloom, who the starlet dated for a little less than a year before the pair split in March

Fun house! Plenty of guests stopped by during the California Gurl's livestream, including Sia, Dita Von Teese and RuPaul

While talking to James, the Bon Appetit singer opened up about the 'maybes' in her past, telling the host '...the one who got away? That's Groban,'

Perry continued, telling Corden the singers are now close pals.

'He's one of my good friends. I love him so much. He's the best,' Katy explained.

Lost love? Katy also revealed her favorite 'could-have-been- boyfriend, telling James that singer Josh Groban is 'the one who got away' but adding that the pair are now 'good friends'

Wouldn't mind doing that again: Topping Katy's list was John Mayer, who the Bon Appetit singer dated on and off during the early 2010's

During Saturday of Katy's full weekend on camera, the Cover Girl spokesgal spent time with Superstore's America Ferrera as they prepared dinner with celebrity chef Roy Choi.

After fixing up some delicious eats, the starlets hosted a fabulous dinner soiree where they were joined by trans activist Gavin Grimm and other special guests along with America's foundation Harness.

Plenty of more guests stopped by during the California Gurl's livestream, including Sia, Dita Von Teese, Aruianna Huffington and RuPaul.

Hostess with the mostest! Katy spent a full weekend on camera, during which time she cooked dinner with Superstore's America Ferrera and celebrity chef Roy Choi

Plenty of fabulous people! Michael Ian Black, Kasey Musgraves, and Gigi Gorgeous were just a few of Katy's Sunday guests at the Witness house

Katy's weekend of Witness World Wide wraps up Monday, but the starlet still has several high profile guests stopping by before the stream ends.

Michael Ian Black will be chat with Katy for his podcast How To Be Amazing with Michael Ian Black,

Singer-songwriter Kacey Musgraves will ream up with Katy to teach fans how to play Kacey's song Follow Your Arrow.

And late Sunday model Gigi Gorgeous will stop by to discuss her YouTube Red documentary This is Everything: Gigi Gorgeous.