Former Jethro Tull frontman Ian Anderson wants fans to know he isn't mouthing along with pre-recorded vocals on his latest tour.

Anderson, currently on the road behind his Jethro Tull: A Rock Opera project, took to Facebook to counter rumors that, as he put it, the shows are "either all prerecorded vocals or, at best, that I am singing only about 30 percent of the words."

Describing those allegations as "utter tosh," Anderson pointed out that the format of his new 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." And to prove he'd held to that 30 percent pre-recorded ratio, he went on to break it down with some math.

Counting narrative lines, Anderson says "there are 589 lines of lyrics in the whole show and I sing in 395 of the lines in total or 67 percent"; without the narrative, he notes, "there are exactly 500 lines and I sing 364 or 73 percent of the lines of the actual songs."

Not only does that uphold the 70 percent average he'd planned on, but as Anderson went on to argue, the show actually leans more on his vocals than a regular Tull concert set. "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," he writes. "Sorry to be pedantic, but just for the record, it’s nice to paint the accurate picture for the fans."

In the end, the annoyance of dealing with rumors aside, Anderson's somewhat flattered that he's facing this particular problem. "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," he concludes. "Trust me -- if you see me with my mouth open and bulging eyes -- it's real!"

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This Day in Rock History: September 29