A blazing argument between US comic Joan Rivers and broadcaster Darcus Howe almost brought BBC Radio 4's Midweek programme to a standstill on Wednesday.
The dispute began when Howe suggested the veteran performer was offended by the use of the term "black".
Rivers replied angrily, calling Howe a "son of a bitch" and accusing him of calling her a racist.
Presenter Libby Purves tried to defuse the row, which was broadcast live on the normally sedate programme.
The dispute arose during a discussion on Howe's forthcoming Channel 4 documentary Son of Mine, which explores his relationship with his 20-year-old son Amiri.
The Trinidad-born broadcaster revealed how he had only seen the boy a few times a year during the first eight years of his life, prompting further sallies from Rivers.
'Chip on shoulder'
"You had a child, you left him," she said. "Where were you when he was growing up?"
Rivers, about to embark on a UK tour, also accused Howe of having "a chip on his shoulder" on the subject of race.
Purves eventually managed to end the argument by bringing in another guest, plant photographer Andrea Jones.
A Radio 4 spokeswoman said the station had received around 20 calls from listeners.
"A few complained about the swearing, but most called to say they really enjoyed the debate," she said.
Son of Mine will be shown on Channel 4's More4 network on 24 October.