The 35-year-old country star made an unexpected appearance at the Bridgestone Arena to deliver an acoustic medley of songs with Urban and Bentley, including Hank Williams' "Your Cheatin' Heart" and the Dixie Chicks' "Cowboy Take Me Away", according to The Tennessean.
After the gig, Bentley took to Instagram to share a snap of the trio, confessing that he had begged Urban to duet with him.
"What can I say about these two and this moment here tonight at Bridgestone Arena, other than it's just good to have pals," he wrote.
"Someone like @keithurban, who I sent a text to two days ago that literally started with 'I hate myself for even texting this, so please just say no, but I'm playing Bridgestone tomorrow night.....' And @mirandalambert, who I randomly bumped into yesterday in Nashville, who asked about the show and said she and her husband were thinking about coming down," he added.
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what can I say about these two and this moment here tonight at Bridgestone Arena, other than it’s just good to have pals. Someone like @keithurban, who I sent a text to two days ago that literally started with “I hate myself for even texting this, so please just say no, but I’m playing Bridgestone tomorrow night.....” And @mirandalambert, who who I randomly bumped into yesterday in nashville, who asked about the show and said she and her husband were thinking about coming down. A lot of laughs in the dressing room 20 minutes before my band and I walked on stage, working something up. The best. Heart full of grateful for everyone that made tonight the night that it was, but these two are at the top. 🙏 #burningmantour #nashville
Lambert's performance came less than a week after she announced she had wed New York Police Department officer Brendan McLoughlin after a whirlwind romance.
"In honor (sic) of Valentine's Day I wanted to share some news. I met the love of my life. And we got hitched!" Miranda wrote on Instagram, alongside two snaps of the newlyweds on their big day. "My heart is full. Thank you Brendan McLoughlin for loving me for... me."
McLoughlin, 27, was first photographed with his "Tin Man" hitmaker wife in New York City, the same day she first shared her exciting news on social media.
Lambert, who was previously married to Blake Shelton, wore her new wedding band and diamond engagement ring, which experts estimate costs up to $20,000 (£15,300), for the impromptu show in Nashville.