Judas Priest's Glenn Tipton is stepping back from touring after being diagnosed with the later stages of Parkinson's disease.

The 70-year-old Grammy Award-winning guitar player insists he's still a member of the heavy metal band - completed by Rob Halford, Richie Faulkner, Scott Travis and Ian Hill - but is having to give up long periods on the road because he's struggling to play the more ''challenging'' songs, due to the symptoms of the degenerative disorder which affects the nervous system.

The 'Breakin' The Law' hitmaker will be replaced by Andy Sneap - who previously played with Priest as well as Megadeth and Opeth in the past - on their tour, which kicks off at the Mohegan Sun Arena at Casey Plaza in Pennsylvania on March 13.

In a lengthy statement posted on Facebook, the band - who release new record 'Firepower' on March 9 - wrote: ''Ten years ago Glenn was diagnosed to have the onset of the early stages of Parkinson's - from then until recently Glenn has lived his life as the great heavy metal guitar player he has always been, maintaining by his own definition a standard of quality and performance that is incredibly important.

''Right now Glenn is able to play and perform some of the Priest songs that are less challenging but due to the nature of Parkinson's progression he wants to let you all know that he won't be be touring as such -

True to the metal spirit of 'the show must go on' Glenn has requested Andy Sneap to fly the flag on stage for him

''I want everyone to know that it's vital that the Judas Priest tour go ahead and that I am not leaving the band - it's simply that my role has changed.

''I don't rule out the chance to go on stage as and when I feel able to blast out some Priest! So at some point in the not too distant future I'm really looking forward to seeing all of our wonderful metal maniacs once again (sic)''

Glenn's bandmates hailed him a ''true metal hero'', and said he would be welcomed back to play at any time.

They added: ''Rob, Richie, Ian and Scott have this to say:

''We have been privileged to witness Glenn's determination and steadfast commitment over the years, showing his passion and self belief through the writing, recording and performing sessions with Priest - he is a true metal hero!

We are not surprised by Glenn's insistence that we complete the Firepower tour and thank Andy for joining us to make Glenn's wishes become real -

As Glenn has said we also can't wait to have him with us at any time any place on the road.....

We love you Glenn! (sic)''