The veteran rocker has been accused of mouthing along to pre-recorded vocals during Jethro Tull: A Rock Opera dates.

Anderson has taken to to counter reports suggesting he is at best "singing only about 30 percent of the words".

Calling the allegations "utter tosh", the singer/flautist writes, "(The show) was constructed from the beginning to allow about a third of the performance to be the domain of the pre-recorded video guests - whether singing solo in-character lines or duets with me.

"There are 589 lines of lyrics in the whole show and I sing in 395 of the lines in total or 67 percent (sic)."

The Thick As a Brick singer adds, "I think it's fair to point out that I am actually singing about the same amount as I usually do in the context of the big picture over the many years. This show has many more sung songs and much less instrumental music anyway. Sorry to be pedantic, but just for the record, it's nice to paint the accurate picture for the fans.

"Looking on the bright side, if it appears to some folk that my contributions as a vocalist are prerecorded, then I must be doing a half-way decent job of singing it live. Trust me - if you see me with my mouth open and bulging eyes - it's real!"