Sir Elton John has stunned fans by launching a scathing tirade against Janet Jackson, accusing his fellow superstar of duping fans by lip-syncing on tour.

The R&B icon, 49, launched her music comeback a year ago (15) with all the release of Unbreakable, her first album since 2008’s Discipline, and after that hit the street for the Unbreakable World Tour.

The shows, her first in four years, started in Vancouver, Canada in August (15) to great reviews, but Elton can’t discover why everyone commended the concerts, because he’s convinced Janet not sings live.

“You know, f**king music magazines writing overview of Janet Jackson saying, ‘This is the best show – four and a half stars,'” the outspoken Brit told Rolling Stone magazine. “It’s f**king lip-synced! Hello! That’s not a show!”

“I’d rather go and pay attention to a drag queen,” the 68-year-old declared, before adding, “F**k off.”

Representatives for Janet, who recently were forced to halt her trek to plod through throat surgery, haven’t yet comment on Elton’s harsh critique, nevertheless the Candle inside the Wind singer established fact for his blunt and brutally honest opinions.

He famously attacked his former foe Madonna way back in 2004, accusing her of miming her way through shows, after she was nominated to the Best Live Act honour at Britain’s Q Awards.

“Madonna, Best Live Act? F**k off,” Elton told the shocked audience. “Since when has lip-syncing been live? Sorry this, but I think everyone who lip-syncs on stage in public areas, after you pay like 75 quid (pounds) to discover them, needs to be shot. Thank you very much. That’s me off her Christmas card list, but do I provide a toss? No.”

The pair has since made amends after a period of petty fighting, and after this Elton admits the Queen of Pop didn’t deserve the vitriol he threw her way.

“I say what I feel,” he continued to Rolling Stone. “I probably went past an acceptable limit with Madonna, and I got very personal and I wrote her (to apologise) – she was very gracious.”