Blake Shelton may have been the man of the hour, but it was his wife Gwen Stefani who stole the spotlight with a heartfelt serenade during an exclusive celebration in his honor.

The country music star hosted a private event at Sidecar in Frisco, Texas, to commemorate a major career milestone - 30 number one singles, on May 7.

But the most touching moment of the night came when Stefani took the stage to perform No Doubt hit Underneath It All for her husband.

Held the night before the Country Music Awards, the event drew an impressive crowd of A-list music industry celebrities.

"Keith Urban was there and the Backstreet Boys were there. There were a lot of A-listers," attendee Christie Chavez, 50, a collections specialist from Frisco said."

"Oh my gosh, it was a celebration."

Christie captured Gwen's tribute on video, as she serenaded her country superstar husband in front of close friends and peers, wearing a double denim outfit and cowboy boots.

She joked she might not remember the words, and reached out to her husband in the front row, who smiled and ran away when she tried to hand him the mic.

The setting - a cozy, rented-out venue described by Christie as "a sports bar grill kind of thing" - offered an intimate space for friends and fellow artists to honor Shelton's achievement."

Shelton's career milestone — 30 number one singles — solidifies his legacy as one of the most successful artists in country music history.