Even the biggest names in country music still have items on their bucket list they'd love to cross off. Maren Morris check off a big one on Wednesday night (April 13), when she was invited to join John Mayer onstage during his Nashville show.

"Hello, Maren can’t be reached right now because she went back to 2006 and told her younger self this would happen in year 2022 and her brain exploded," Morris writes in a social media post shared the day after.

It's clear that the "Circles Around This Town" singer is a fan of Mayer — she further praised him in the caption of her post, thanking the pop singer-songwriter for "bringing your new light to Nashville and blessing our ears."

Mayer made a Nashville stop on his Sob Rock Tour, and when an artist hits Music City, there's always a chance for a surprise guest. Most can have their pick of the musical talent litter, so long as schedules align.

Morris joined the longtime musician for his aching breakup song "Slow Dancing in a Burning Room," from his 2006 Continuum album. The two effortlessly traded lyrics on the tune, with the audience singing along.

The crowd laughed and cheered as Morris changed one line to fit her needs better — skip to the two-minute mark in the video below to hear it:

This is hardly the first time Morris has danced outside of country music. In 2015, she performed alongside Taylor Swift on her 1989 Tour stop in Arlington, Texas, to sing "The Middle," Morris' collaboration with Zedd, who is also not country. The Humble Quest artist even accompanied former One Direction member Niall Horan on his 2018 Flicker World Tour.

Morris will embark on her own tour, the Humble Quest Tour in support of her new album, this summer. Dates will get underway June 9, with Ruston Kelly, Brent Cobb, Natalie Hemby, Joy Oladokun, and Brittany Spencer serving as supporting acts on various shows. The trek wraps on Dec. 2.

Humble Quest — her third major studio country album — was released in March.

See the Top 50 Country Duets of All Time!