Katy Perry, John Mayer Are 'Perfect Together' On 'Who You Love'

Katy Cats review her boyfriend's new song, telling MTV News, 'I'm really excited to see her bring those roots back.'

While the Katy Cats were out celebrating the release of Katy Perry's new single, "Roar," and her upcoming performance at the 2013 MTV Video Music Awards on August 25, her duet "Who You Love" with her on-again, off-again boyfriend John Mayer hit the 'net.

On the folky tune, from Mayer's upcoming August 20 album, Paradise Valley, the two singers trade lines about falling for one another. At the end of the track, Perry even lets out a little "love giggle." Fan Juliette told MTV News, "They're perfect together. I think that it's going to be a really big success."

Carlos added, "They're both good artists, and I think it's always a good idea to link [up on] a duet."

Katy's fans told MTV News they are excited to see Perry flexing her vocal cords on a genre of music she doesn't tend to explore very often. "Obviously, their music is very, very different, but I like a lot of Katy Perry's acoustic stuff, like 'Mannequin' from One of the Boys," Gabe said. "I'm really excited to see her bring those roots back. I'm all for love, and ... if they're happy, they're happy, and people should just let them be."

In addition to appearing on Mayer's album, Perry confirmed that the musician also played guitar on her October 22 album, Prism. Now, fans have two albums on which to listen to the singers make sweet music together. "I love it. I love John Mayer, love his music," Morgan said. "I was hoping they would collaborate on something anyway, so I love it."

Elsewhere on Twitter, fans declared the acoustic ballad "too cute" and "simplistically beautiful." It's also being billed as the perfect jam for your next wedding.

Perry is slated to perform at the VMAs on August 25 when the show goes live from Brooklyn's Barclays Center. She'll perform her new single, "Roar," for the first time ever, joining a slew of other A-listers set to take the stage including Lady Gaga, Kanye West, Miley Cyrus and Robin Thicke.