Katy Perry says John Mayer is an ''incredible'' boyfriend.

The 'Roar' hitmaker, 28, gushed about the singer-songwriter as she helped promote his new album 'Paradise Valley' by urging her fans to buy a copy.

The brunette beauty wrote on Twitter: ''Something VERY special is happening at midnight EST tonight on iTunes! My incredible, inspiring boyfriend John Mayer will release a spectacular record called 'Paradise Valley' check it out here.''

The couple, who recently released their first duet 'Who You Love', has been very supportive of each other's new music and John, 35, voiced his love for his girlfriend's single last week.

He said: '''Roar' is in my life. I remember hearing it, going like, 'Wow what an interesting experience' to hear something that you identify as massive before it's massive.

''I thought it was a really sweet, unforgettable sort of experience to hear someone's work while they still have a very nascent relationship with it.

''In a way you get swallowed up by it, it's so big. Because it's such an incredibly big song that it doesn't need you to tell anybody, while you're eating lunch, [that] millions of people are going to be dancing on tables to that.''

The couple first began dating after Katy divorced Russell Brand in February 2012 but split in March 2013. They reunited two months later.