Katy had just come out with I Kissed A Girl and One Of The Boys when she was romancing Groban.

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

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.

Josh Groban