Madonna has grown out her armpit hair, and shared a picture via Instagram to prove it on Thursday, March 20 Credit: courtesy of Madonna

Someone needs to buy a razor! Madonna's growing out her armpit hair -- and to prove it, she proudly shared a close-up snapshot via Instagram on Thursday, March 20.

"Long hair......Don't Care!!!!!!" the 55-year-old music superstar captioned the pic. "#artforfreedom #rebelheart #revolutionoflove." In the photo, Madonna raises her right arm above her head, revealing a patch of brown hair underneath her arm. She also is wearing a black bow tie and a cleavage-baring bra.

The "4 Minutes" singer has been putting her Instagram to good use as of late. On March 16, she channeled actress Emilia Clarke's Game of Thrones character Daenerys Targaryen for Purim by wearing what appeared at first to be a replica of her costume. Three days later, Clarke revealed Madonna's get-up was the real deal.

"It's my real costume," Clarke, 26, said during an appearance on The Tonight Show With Jimmy Fallon on March 19. "I thought I was dreaming. I got an email from amazing HBO publicist Mara, saying, 'Madonna would like to borrow the costume, is that okay?'"

She continued: "I thought, 'God, this must be a dream. This can't be real.'"