Pink Floyd's Roger Waters has been accused of being an "anti-Semitic, misogynistic, Putin apologist" by former bandmate David Gilmour and his wife Polly Samson.
Samson, a novelist and songwriter who co-wrote lyrics to several Pink Floyd tracks with her husband, launched the public attack on Waters on Monday night.
The broadside appeared to be a response to an interview Waters gave to German newspaper Berliner Zeitung on Saturday in which he attacked Israel and appeared supportive of Russia.
An English translation of the interview posted to Waters' website includes the rocker doubling down on previous incendiary comments comparing Israel to Nazi Germany.
Asked if he stood by the comments, he said: "Yes, of course. The Israelis are committing genocide. Just like Great Britain did during our colonial period, by the way."
Waters tweeted a link to the English translation of the article over the weekend, defending himself against charges of anti-Semitism.
He wrote: "The truth will set us free", adding that the German publication had "courageously" published an in-depth interview with him “against the backdrop of the outrageous and despicable smear campaign by the Israeli lobby to denounce me as an anti-Semite, which I am not, never have been and never will be”.
The Pink Floyd co-founder, who has previously called Vladimir Putin a "gangster", faced a storm of criticism and concert cancellations last year after defending some of Russia’s actions in Ukraine.
Waters criticised the West's response to the war in his interview with the Berliner Zeitung, saying: "The most important reason for supplying arms to Ukraine is surely profit for the arms industry.
"And I wonder: is Putin a bigger gangster than Joe Biden and all those in charge of American politics since World War II? I am not so sure. Putin didn’t invade Vietnam or Iraq?"
In a post on Twitter, Samson addressed Waters directly, telling him he was "anti-Semitic to your rotten core".
She went on to make a string of other accusations, including accusing him of being a "misogynistic, sick-with-envy, megalomaniac”. “Enough of your nonsense,” she added.
Gilmour made clear he supported his wife's comments, later tweeting: “Every word demonstrably true.”
It marks a deeply personal turn to the decades-long feud between the iconic rock band's famous frontmen.
Pink Floyd was formed by Waters, Nick Mason, Richard Wright and Syd Barrett in 1965. Gilmour joined in 1967.
The rock band was one of the most successful of the 1970s, but became mired in disputes over its creative direction that led to Waters' exit in the 1980s.
In a statement on Twitter, Waters said he was “aware of the incendiary and wildly inaccurate comments made about him”.
He denies the claims and is seeking advice, the statement concluded.