Bubblegum K.K.
From Nookipedia, the Animal Crossing wiki
"Bubblegum K.K." (けけアイドル, K.K. Idol) is a song introduced in Animal Crossing: New Leaf. Unlike many of K.K. Slider's other songs, this song has a cheerful beat.
Both Chrissy and Francine appear on the song cover. Gayle, Graham, Penelope, Rosie, Cece and Rilla play the song in their houses in Animal Crossing: New Leaf.