Gwen Stefani may be head over heels with boyfriend Blake Shelton, but little did fans know that the former No Doubt frontwoman used to hate country singers. 

Blake Shelton joined his girlfriend's holiday special titled "You Make It Feel Like Christmas" on Tuesday, Dec. 12, on NBC. The couple performed their holiday single of the same title, and they were, evidently, so in love.

Stefani looked so festive with her red outfit, while her 41-year-old boyfriend was wearing his signature jeans and jacket. Surprisingly, they did not reveal major PDA on stage, but they, obviously, could not take their eyes off from each other.

In a special skit Stefani made, she revealed a young version of herself saying that she actually hates annoying country singers. Her present self then said that she will be "in for a big surprise" as Santa is going to pair her with a country singer one day.

In an interview with Entertainment Tonight, Gavin Rossdale's ex-wife said that it is interesting what love can do and "how dangerous it can be." She also said that it has the ability to break and save someone at the same time. "I feel like it's very Christmassy, because Christmas is about being saved, really," she described her and Shelton's performance.

In a different interview with People, Shelton, on the other hand, talked about working with his girlfriend on a duet with "You Make It Feel Like Christmas." "She was so excited," he said.

Miranda Lambert's former husband said that while he was driving one day, Stefani called him and told him about writing a song. Shelton shared that he loves seeing the former "The Voice" coach happy. He could especially see this when she is writing a song, hearing how merry she is in her voice, and seeing how she is so into what she is doing.

With that, he thought of a way to help her by getting his guitar, writing the chorus' melody, and coming up with lyrics. From there, he sent his part of the song, which ended to be the track's first verse.