Madonna has sparked online debate by uploading a photo of herself showing off some armpit hair.

The singer took to Instagram earlier today (March 21) to post a picture of herself with her arm aloft and showcasing pit hair.

She wrote: "Long hair......Don't Care!!!!!! #artforfreedom #rebelheart#revolutionoflove."

It generated some varied responses in its comments section, with one user saying:

"Disgusting. Trying 2hard 2stay relevant."

Another user said: "Only M can pull this off!"

One other commenter replied: "To All of the guys saying that's hot wow omg. I know damn well that if this wasn't Madonna and you guys saw a girl with armpit hair you would be disgusted and not waste your time with that girl."