American pop singer-actor Janet Jackson thinks bald women look "beautiful" and was keen to shave her head ahead of her 1993 world tour.

Jackson shared on Twitter after sharing an Instagram video featuring a young cancer sufferer named Gaby, whose older sister Camila shared that her sibling thought she looked ugly because she had lost her eyebrows, reports femalefirst.co.uk.

Camila then shocked Gaby by taking a razor to her own brows and telling her: "These don't make you pretty. They don't make you."

Jackson captioned the video: "This made me cry. I was actually going to shave my head for the janet. Tour. I love a bald head on a woman. I think it's beautiful! You & your family are in my prayers. Stay positive & strong. You're so beautiful [prayer emojis] RT with a (heart emoji) to send love and support."

Jackson's post attracted singer Rihanna and actor Michael B. Jordan.

Rihanna commented: "Wow! We (heart emoji) you Gaby."

Jordan wrote: "keep fighting!!"

Singer Kelly Clarkson also shared the video on her Twitter account and praised the "beautiful and powerful" sisters.