With her mystical and witchy vibes, Stevie Nicks has always been one of Katy Perry's idols. She once told ABC that she "sees straight through my soul." So when the Fleetwood Mac leading lady dedicated a song to Perry at last night's concert in Las Vegas, well, she was speechless.

That's when boyfriend John Mayer took over.

"John here," he wrote on KP's Twitter handle. "Katy can't write because she's getting over Stevie Nicks dedicating Landslide to us at the Fleetwood Mac concert. Unforgettable."

And just because they're Katy Perry and John Mayer and they might just be the cutest celeb couple at the moment (Kimye, step aside), he continued, giving us a little snippet of what it's like being "unconditionally" in love at a Fleetwood Mac concert.

"While I'm at it I have a couple things I'd like to get off my-oh, she's motioning for the phone back. Gotta go!! -JM"

Sounds like John should start tweeting more often. His account seems to be run by his team, but hey, "say what you need to say," John.

To close out 2013, the couple is still in promo mode for their "Who You Love" video from the song off Paradise Valley. The two took the stage together for Mayer's tour closer in Brooklyn to sing the duet and have been making the press rounds on "Ellen" and "Good Morning America."

And if things keep going well for the two, who knows, maybe Stevie will be around to officiate their wedding, just like she did for Vanessa Carlton on Friday.