The singer explained that she was dropped from three record labels before she signed with Capitol in the US and had to fight to retain her sense of identity.
"There was a lot of the word 'no' being thrown my way and I just never accepted that," Perry told The Ellen DeGeneres Show.
"You know overcoming everybody saying, 'It's not going to work', because a lot of people wanted me to be like someone - whether that was a Kelly Clarkson or an Avril Lavigne - and I was like, 'I want to be Katy Perry first', and they didn't really understand that."
She added: "Maybe because my vision was so strong, but finally I got to go with it and it's kind of worked out."
Katy Perry will officially release her new single on July 2, while her concert film Part of Me 3D will follows on July 5.
Watch Katy Perry on The Ellen DeGeneres Show below: