LONDON, United Kingdom - Rolling Stones frontman Mick Jagger is "very well-endowed," his ex, Jerry Hall, has said in response to his bandmate Keith Richards's claim that the singer had a "tiny todger".

Hall stepped in after Richards used his autobiography, "Life", to cast aspersions on the size of Jagger's manhood and give details of how the pair shared trysts with glamorous women.

"Mick is very well-endowed," Hall told BBC radio. "I should know -- I was with him for 23 years. Keith is just jealous."

Jagger and Hall, a model from Texas in the United States, had four children together before splitting up in the late 1990s.

Richards's no-holds barred memoir, being published later this month, details his fraught relationship with songwriting partner Jagger, whom he calls "Your Majesty" or "Brenda" -- also a nickname for Queen Elizabeth II.

Richards adds that Jagger became "unbearable" from about the early 1980s.

"I used to love Mick, but I haven't been to his dressing room in 20 years. Sometimes I think, 'I miss my friend'. I wonder, 'Where did he go?'," writes Richards, now 67.

He also claims that Jagger has a "tiny todger", a detail apparently passed on to him by Jagger's one-time girlfriend Marianne Faithfull, whom he also slept with.

Faithfull was involved in a series of complicated love trysts involving the Stones, which began when Richards stole his bandmate Brian Jones' girlfriend, Anita Pallenberg, on a drug-fuelled trip to Spain.

Later, Richards became convinced that Pallenburg was having an affair with Jagger and slept with Faithfull -- only to be forced to escape through a window when Jagger came home early, leaving his socks behind.

Jones died in a swimming pool in 1969, but Richards and Pallenberg went on to have three children together.