Both recently single, Stefani and Shelton performed “Hotline Bling” during a taping of The Tonight Show Starring Jimmy Fallon. Fans speculated that sparks are flying between the two, and relationship rumors started to gain traction.

To wit: Blake Shelton’s onstage response Thursday evening at Rupp Arena to an audience sing-a-long that grew out of “Strawberry Wine,” the 1996 hit served up solemnly by Deana Carter, the second of three guests making up this opening night bill of the headliner’s Friends and Heroes Tour.