Soul icon Aretha Franklin has axed two upcoming concerts to undergo treatment for another mystery condition.

The Respect hitmaker was due to perform with the Chicago Symphony Orchestra in Illinois next Monday (20May13) and hit the stage at the Foxwoods Resort & Casino in Connecticut on 26 May (13), but both dates have been cancelled on the advice of doctors.

Details about Franklin's medical issue have not been released, but it's not the first time she has scrapped gigs due to her health.

She called off a series of shows in 2010 and refused to divulge details about what ailed her for two years, until revealing in early 2012 that she had undergone surgery to remove a tumour - although she did not specify where on her body the growth was found.

The 71 year old has also battled health problems with her legs and feet, which forced her to pull out of performing at Whitney Houston's funeral last year (12).

Singer Janelle Monae has stepped in to replace Franklin at the Illinois show.