Tina Turner looks unrecognisable in rare new photo ahead of upcoming documentary

After years spent battling ill health, Tina Turner has reappeared in a rare new photo to celebrate her upcoming "farewell" documentary.

The photo is one of the first times fans have seen the 81-year-old, who has largely retreated from public life after being plagued by ill health in recent years including a stroke, cancer and a kidney transplant.

Taking to Instagram to share the picture ahead of the global release of her Tina documentary, she wrote: "Only 5 days left! This Saturday, the documentary "TINA" will be released.

"I am so excited to share this movie with you – seeing the concert scenes made me relive some of the proudest moments of my life. I simply had to sing along and dance around my living room!"

The film is described as "a revealing and intimate look at the life and career of musical icon Tina Turner, charting her improbable rise to early fame, her personal and professional struggles throughout her life and her even more improbable resurgence as a global phenomenon in the 1980s."

Turner herself was interviewed for the project, at her home in Zurich and the project will feature "a wealth of never-before-seen footage, audiotapes and personal photos, telling a deep and absorbing story about the queen of rock ‘n’ roll in all its complexity."

With archival footage spanning over 60 years worth of interviews, performances and personal moments, Tina is set to be an in-depth look at the life of the music legend unlike any fans have seen before.

Additionally, interviews were conducted with numerous stars and those intimately familiar with Turner's life, including Angela Bassett, Oprah Winfrey, journalist Kurt Loder, as well as Turner's husband, Erwin Bach.

Tina will be available on HBO and HBO Max on March 27.