Rio de Janeiro, Brazil - This mother truly is her daughter's best friend.

Luciana Rebello has had a tough few weeks, sharing her dramatic story on Instagram and Facebook: she was diagnosed with cervical cancer, which was caused by HPV (human papillomavirus).

Before starting her chemotherapy, the Brazilian decided to shave off her hair completely – after all, sooner or later it would fall out anyway.

On her Facebook page, she shared a video of her mother first trimming her blonde mane with scissors, before completely shaving it off with clippers.

Then something completely unexpected happens: by the time Luciana's mother is about halfway through, she takes the clippers to her own hair and begins to shave it off!

The 31-year-old, who clearly had no idea of what her mother was about to do, is deeply moved by the gesture and begins to cry.

"A mother's love," she captioned the emotional clip, that has already touched the hearts of millions of internet users.

The recording has since spread rapidly not only on Facebook, but also on Twitter.

"I cried when I saw this, this is unconditional love for your child," one user wrote.

Another one recalled doing the same for his father: "It brings back touching moments. It was tough but also liberating to shave my head in support. Thanks for sharing."

Luciana wanted her video to encourage others suffering from cancer and to make women more aware of the danger of HPV.