Janet Jackson's mystery illness has been confirmed as migraine-related vertigo - despite her brother Randy earlier denying he had revealed she suffered from the condition.

The superstar singer has been forced to cancel nine dates on her Rock Witchu tour, after the illness stopped her from performing.

Jackson axed her first show in Montreal, Canada on 29 September after checking into a city hospital.

Soon after, her brother Randy reportedly told a Michael Jackson fan site that his sister had to withdraw from the show because she suffered from vertigo - a condition which makes the sufferer feel unbalanced and dizzy.

Randy quickly denied the reports, insisting an imposter broke the bogus news, insisting the exclusive "interview never happened".

However, Jackson's representatives have now released a statement stating the star has been diagnosed with "migraine-associated vertigo" - dizziness brought on by severe headaches.

A spokesperson tells E! News, "After a thorough medical evaluation, it has been confirmed that Janet's symptoms are being caused by a rare form of migraine called vestibular migraine or migraine-associated vertigo for which she is currently receiving treatment."