Who sings la la la la la song?

Well, there are several "La La" songs that come to mind:

"If You Seek Amy," by Britney Spears starts out with "La Las" and repeats the same "La Las."

Ashlee Simpson has a song called "La La." I guess that was around 3-4 years ago.

"Loving You," by Minnie Ripperton has a "La La" section.

"La La La" by Naughty Boy.