Aretha Franklin is planning to sue the writer of a new unauthorised biography.

The 72-year-old singer is furious with David Ritz - who ghostwrote her 1999 autobiography 'From These Roots' - over his new tell-all tome 'Respect' and has branded the claims he makes in the book ''lies, lies, lies''.

She told the Detroit News newspaper: ''There's a very trashy, trashy book on the street . . . It's lies, lies, lies and then more lies.

''I'm talking to a criminal attorney. If this isn't defamation, I don't know what would be.''

Aretha is believed to be upset about claims made about her sexual promiscuity on the 1950s gospel circuit, but the author - who narrates the new book through interviews with friends, family and associates - claims the material was cut from her autobiography.

Fellow singer Etta James is quoted as saying: ''I can understand Aretha not wanting to talk about that . . . Who wants to admit that you're praising the Lord at the 8 p.m. service and servicing some drop-dead gorgeous hunk of a singer an hour later? Aretha and I started out before we were teenagers . . . we wanted to experience it all. I wouldn't use the expression sexually active, I'd say sexually overactive.''

While the 'Respect' hitmaker is upset by the book, writer David insists it is meant as a tribute.

He told the New York Post newspaper's Page Six column: ''I spent 25 years researching 'Respect.' I see my book as an homage to Aretha's artistic genius and an empathetic portrait of a woman who has survived and thrived in the complex culture of show business.''