The legendary Stevie Nicks dedicated her song "Landslide" to her and John Mayer during a Fleetwood Mac concert in Las Vegas.
Katy was so starstruck by the shout out that John had to take over her Twitter just to tell fans the amazing news.
"John here. Katy can't write because she's getting over Stevie Nicks dedicating Landslide to us at the Fleetwood Mac concert. Unforgettable," he wrote.
He then joked that there was more he wanted to write, but that Katy was asking for her phone back.
We can't say we blame her, manning her Twitter account is a huge responsibility as she's currently the most followed celeb on the popular social media site, with over 49 million followers.
In fact, if Stevie had a Twitter, she would probably be one of those 49 million, as she and Katy recently struck up a friendship.
"She is a beautiful woman," Katy said during a Sirius XM Townhall Q&A. "She just has so many little nuggets of wisdom and sees straight through my soul."
Stevie has also been a fan of Katy's for quite some time, saying back in 2011 that she loved Katy's song "E.T" and promising that she would do a song with her one day.
Well, what are you waiting for, ladies?