She's notoriously private. He admits he sometimes says too much. But katy perry and john mayer are now together. Talking about their love and their first joint interview today on "good morning... See More
She's notoriously private. He admits he sometimes says too much. But katy perry and john mayer are now together. Talking about their love and their first joint interview today on "good morning america." David wright reports. ♪ My boy ♪ Reporter: A loving duet debuted on "good morning america" this morning. ♪ You love who you love ♪ Reporter: The only hint of the turmoil of celebrity romance. Katy is a superstar for a reason. Reporter: In real life, katy perry and john mayer may have had their ups and downs, as they told george stephanopoulos today they're emphatically back together. The two of you never sat down for a tv interview together. We don't know what kind of body language we are supposed to be exhibiting. Reporter: For two public figures, it's not easy. You get too close, too touchy feely. Get too far away, they say i don't see chemistry. John mayer's music tend to be inclusive and brings people in. Katy perry like is a great anthem. And for them to join on a song like this makes a lot of sense. Because it is a great time for the two of them. The romance is young. And why not celebrate. Reporter: There is something magical about professional peers finding romance in real life. Beyonce and jay-z come to mind. Pop royalty. The king and queen steeem to be in perfect harmony. It can be tricky as kristen stewart found out the fairy tale can come back to bite you. The issue with celebrity romance is that if you break up the audiences tend to pick sides. Reporter: Some times celebrity romance cuts against the plot. I heard everything. And revenge. Emily is out to get. In real life, they are a couple. Thankfully for him all that intrigue seems to beep jugined up for tv. Pop music may be a special case for this time of thing. ♪ Because I knew you were trouble when you walked in ♪ Reporter: Taylor swift has practically made a career out of the breakup song. ♪ We are never, ever, ever, getting back together ♪ Reporter: There is one for each partner. Of course there is the possibility of revenge songs. . Sarah silverman perfected that art for her ex jimmy kimmel. This is some stuff of yours that you left when you left. Reporter: Which is not to wish any bad charma on katy perry and john mayer. Clearly in the first blush of romance, and expressing it in song. It's more about the message of the song. Reporter: Here's wishing them all the magic will last. I'm david wright for "nightline" in hollywood.
This transcript has been automatically generated and may not be 100% accurate.