Don Imus has been sued for more than $4 million by an advertiser on his former CBS radio morning show who claims the radio personality “insulted” a product he was supposed to promote.

Last year, while radio shock jock Don Imus was still working at CBS-owned WFAN radio station in New York, he was supposed to promote a book by the late President Gerald Ford for Flatsigned Press Inc., a book publisher based in Nashville, Tenn. and he apparently did a bad job of it.

Flatsigned filed a $4 million lawsuit against Imus Wednesday in Manhattan's state Supreme Court, asking for compensatory damages for breach of contract, libel and malice, and for another $59,000 spent for a newspaper ad that ran after the commercials on Imus’s show, the Associated Press reports.

What Flatsigned is so upset about is the unscripted joking Imus did in January 2007 at the expense of the publisher’s book “John F. Kennedy: Assassination Report of the Warren Commission,” written by former President Gerald Ford, who passed away in December 2006.

Marc Held, Flatsigned's lawyer, said Thursday that Ford approved the book and signed the copies Flatsigned was selling, the AP reports. Imus was told to read the script “word for word” but instead chose to “insult” the sponsor, Held said.

Imus told listeners that the company’s commercials for the book were “cheesy” and commented that the publishers had “been waiting for (Ford) to croak so they can unload these (books),” the lawsuit claims.

The commercial asked for Imus to specify Ford had hand-signed the books before he died and Imus spiced up the text by commenting, “How else would he sign them, with his foot?” the lawsuit says.

Court papers say Imus first read the script as written but in later readings brought a personal – and unrequested – contribution. Flatsigned alleges the consequences of Imus’ actions were that stores refused to stock the book and that sales dropped $40,000 a day for several months after his “libelous and disparaging comments.”

Flatsigned said it paid for two 30-second ad scripts a day for three days — Jan. 29, 30 and 31, 2007.

Martin Garbus, Imus' lawyer, is quoted by Reuters as saying, “The lawsuit is without merit and will be dismissed.”

Imus’ former bosses at CBS Radio, owner of WFAN, have also been sued. CBS Radio fired the radio shock jock in April following his racist comments of the Rutgers University women's basketball team.

He retuned to the airwaves in December, with a morning show on New York’s WABC.