Legendary rock band Led Zeppelin is rearranging its tracks since lead singer Robert Plant is struggling to hit high notes.
The band has been rehearsing the songs in lower key as the 59-year old Plant is struggling with his voice, which has become deeper, online edition of the Sun reported.
A source revealed, "He and guitarist Jimmy Page have had a few heated discussions about the upcoming gig. Jimmy is a bit rusty and Robert has been struggling with high notes. To avoid any embarrassing vocal wobbles with the world watching, they decided it would be best to transpose the songs in a lower key."
The band will perform at London's O2 arena Dec 10 for the first time after 19 years.
Credits for the info to Sify.com.