Let’s talk about pop stars who actually do play instruments in live/studio settings, despite not being known for it.
The voice is still an instrument = 0 pts
Obv Prince = 0pts
I remember on an older series of X Factor (2012 was the only one I watched, so must be that?) Katy Perry debuted The One Who Got Away on an acoustic guitar. I was in tears by the end - the single version isn’t as good.
See also, Justin Timberlake at the piano for 'Til The End of Time.