It all started when Stefani praised Miley Cyrus' performance of "Prisoner" on NPR's Tiny Desk Concerts series. Cyrus shared her excitement over Stefani's compliment and told the pop star and her groom-to-be that she'd love to be the wedding singer for their upcoming nuptials.
"ALSO @gwenstefani @blakeshelton I'll be your wedding singer! I promise to be on my best behavior. Or worst. whatever you want!" Cyrus wrote. "It's your special day. Cheers to loving you both almost as much as you love each other!"
In a recent interview with People, Shelton praised Cyrus' voice, comparing her vocal talent to his current The Voice co-star, Kelly Clarkson.
"Miley is one of the most talented singers I have ever met," Shelton said. "She drives me crazy because she's a lot like Kelly [Clarkson] in the way that they can burst out with this voice...If I'm going to sing, I have to think about it and go warm up. It's unfair."
As for whether the famous couple will take Cyrus up on her offer, he says he'd love to have Cyrus at the wedding, but he's also hoping for an Adam Levine performance with Levine's band Maroon 5.
"Gwen was showing me that she even said, 'I promise to be on my best behavior,'" Shelton says. "I've known Miley long enough [for her to have to say], 'By the way, I'll be nice when I get here.' So that was nice of her. I don't know what we're going to do, but I still say Adam owes me a full-band performance with Maroon 5, mostly because I want it to cost him. I would rather have Miley as a human being."
Cyrus has served as a coach on NBC's The Voice, which Stefani and Shelton have both starred on. (Shelton and Stefani met on the set of the singing competition and began dating in 2015 after Shelton ended his four-year marriage with Miranda Lambert and Stefani ended her 13-year marriage with Gavin Rossdale.) And as the Nashville, Tennessee-raised daughter of Billy Ray Cyrus, Miley seems like she'd be comfortable at a country wedding if Blake and Gwen decide to get married on their Oklahoma farm.
Cyrus recently released her seventh studio album Plastic Hearts, which features collaborations with Stevie Nicks, Joan Jett and more. She's also featured on her godmother Dolly Parton's 2020 Christmas album A Holly Dolly Christmas.
Gwen Stefani released her new single "Let Me Reintroduce Myself" last year, while Shelton recently shared his latest single "Minimum Wage."
Shelton and Stefani announced their engagement in October of 2020.
"Thanks for saving my 2020...And the rest of my life," Shelton wrote to Stefani in a sweet social media post.
Shelton has already bonded with Stefani's three children.
"Blake told her boys that he wanted to propose and asked their permission," a source told PEOPLE last year. "Her family very much approves of him. He's an amazing partner and a great extra dad to the boys. Gwen is ecstatic. The proposal was a surprise."