They're back together and more loved-up than ever.
So how did Katy Perry, 28, manage to finally tame the wild beast that is John Mayer?
Well, she's been sending him to boyfriend school.
Now's learnt that Katy's asked her BF, 35, to take commitment classes with a renowned New York therapist to prove he can take their relationship seriously.
He's been to two sessions since they reunited in May - and it's already paying off.
On 6 July notorious ladies' man John made a public declaration of love for Katy.
On stage on his Born And Raised tour in Milwaukee, he dedicated a song to her, saying: 'She was so patient.
'[She took time] to get to know me and love me.'
And we hear John has plans to take Katy on a romantic break next month to the £2,600-a- night Makena Kai Estate in Hawaii.
It was where they stayed late last year.
Katy and John first hooked up in August 2012 but have had an on-off romance, splitting up twice already, most recently in March.
Our source says: 'He's told her that he's changed.
Another womanizing egomaniac, I like both Russell and John but neither are relationship material, I hope she doesn't get her heart broken again.
Not too mention they are both ugly. Given how Katy looks it shocks me how she always dates ugly guys that treat her poorly(Travis Mccoy, Russel Brand and John Mayer)
I love them together.
