During a recent Gene Simmons solo concert in Australia that featured ex-KISS guitarist Ace Frehley, the KISS co-founder and mouthpiece took a potshot at Paul Stanley's growing tendency to lose his voice, or sing in a noticeably strained voice, onstage.

Before Simmons invited members of the crowd onstage to sing "Rock and Roll All Nite" (video below) he said, "We need some help, though. We can't sing the song ourselves 'cause I'm 69 and I've lost my voice!" Then Simmons coughed the word "bullshit."

It wasn't the only time Simmons has mocked Stanley's vocals. At an earlier concert, Simmons said, "I'll sing everything because my voice always works. I don't lose my voice. I don't lose my voice... Paul Stanley."

Stanley vocal problems have been well documented and in 2011 he had surgery to cope with "recurring vocal issues."

During his radio show earlier this week longtime KISS fan and established radio host Eddie Trunk emphatically commented about Simmons' callous onstage jokes. "I was shocked when I saw and heard [the] video of Gene and his own band with Ace Frehley standing next to him... Now you're dealing with a guy in Paul, who is ultra-sensitive.... This is his partner. I don't know what Gene was thinking. Look, I'm a guy that always likes guys being honest and outspoken, so okay... But can you believe that he took that opportunity to take a swipe? Wow, I would love to be a fly on the wall at the next KISS meeting and see how that one gets processed."

KISS launch a three-year world tour next year. So, surely they'll have worked out all their personal and professional problems by then.

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