John Travolta and attorney Marty Singer are being sued by Robert Randolph, the author of the self-published book You'll Never Spa In This Town Again, in which Randolph claims he witnessed Travolta having sexual relations with men in gay bathhouses.

Randolph claims that Singer soiled his reputation in a 5-page cease-and-desist letter published by Gawker.com.

In his book, Randolph claims he witnessed Travolta involved in Los Angeles' “secret gay spa subculture.”

“I walked in and the guy was giving John a blowjob and, like guys do, he pulled his head up when I walked in. Then they left the room,” Randolph said. “I followed them up there [to an empty massage room] and … watched them have sex. Full-blown sex. Anal.”

“I've seen people sucking his dick,” he added. “I've seen him sucking other guys' dicks. Anal wasn't always involved. But there was always action of some kind.”

Randolph also describes the men Travolta is attracted to: “His taste has changed over the 15 years that I've seen him visiting spas. … He does do more masculine gay guys, but his thing is straight guys.”

Randolph's allegations against Travolta have also appeared in tabloids the National Enquirer and Star.

Singer countered that Randolph could not be believed because, among other things, he spent time in mental institutions and a 2003 attack left him brain damaged.

Randolph is asking for unspecified damages for trade libel, intentional interference with prospective economic advantage and negligent interference with prospective economic advantage.

Singer called the suit “ridiculous” in statements to TMZ.com.

“It is based on our letter which was completely privileged under the law. We intend to sue the attorneys for malicious prosecution after the court promptly dismisses this baseless lawsuit,” he said.

Travolta has also denied the claims of two male masseurs who claim the actor attempted to initiate sex with them.