Katy Perry has revealed Madonna was "super nice" to her when she first started in the music industry.
The Fireworks singer explained she'd had to earn the veteran pop star's support.
"Madonna was really nice to me," Katy, 39, told Australian TV show The Project.
However, she acknowledged it wasn't easy to obtain Madonna's tick of approval.
"Well, it took a minute because she was testing me," Katy added. "And then she became super nice to me."
Without revealing exactly how Madonna, 66, had "tested" her when they first knew each other, Katy was happy to elaborate on how the more experienced star had encouraged her.
"She just does her Madonna thing," Katy explained. "She would invite me to a party and we had to do a photoshoot together which was amazing. She's the greatest."
She went on to describe how Madonna had mentioned her 2007 single "Ur So Gay" during a radio interview, which had given her career a significant boost.
"She actually shouted out my song and that was really the beginning of my career," Katy explained. "That's kind of what started to break me."
Katy, who turns 40 in October, concluded by declaring she owes the release of her latest album, 143, to Madonna.
"Every female artist still needs to continue to say thank you," she said. "I'm 40 I still get to do music because of Madonna!"