Comedian Tom Dreesen has died aged 86. No cause of death has been revealed but the star died at his Los Angeles home, according to reports.

The star was best known as being the opening act for Frank Sinatra for 14 years. He also pushed for stand-up comedians to get paid at The Comedy Store and partnered in a pioneering interracial act with Tim Reid. Dreesen made hundreds of television appearances throughout his 50-plus years in the entertainment industry, including dozens on The Tonight Show Starring Johnny Carson and on the late-night programmes hosted by his close friend David Letterman, a bond forged during their time together at The Comedy Store in West Hollywood in the 1970s. Leading the tributes to Dreseen's death, Letterman said in a statement: “Tom was the first comedian I met at Comedy Store in 1975. We became friends immediately. He had wisdom and endless stories.

"Everyone admired him, looked up to him and wondered if he ever stopped talking. He never did, he never will. We love him for that. We’ll miss the stories. God bless you Tom.”

Having warmed up crowds for the likes of Liza Minnelli, Smokey Robinson, Gladys Knight and Sammy Davis Jr, the ever-immaculate Dreesen began appearing on the same bill as Sinatra in 1983, forging a remarkable bond with the Chairman of the Board during the legendary singer's final years.

Dreesen soon found himself opening for Sinatra in Atlantic City, little knowing the profound effect it would have on his life. "I thought, 'Yeah, I'll go one week. I'll get my picture taken and I'll hang it in every bar back in Chicago and that will be the end of that,'" he recalled.

"On the second night, Frank and his wife, Barbara, took me to dinner, and in the middle of dinner he put down his knife and his fork. He said, 'Kid, I like your material. I like your style. I'd like you to do a few other dates with me if you're interested.' I said, 'Yeah!' and it turned into 14 years, 45 to 50 cities a year."

The pair cultivated a profound friendship, with Dreesen regularly visiting Sinatra at his Palm Springs compound. He served as a pallbearer and delivered a eulogy at the entertainer's funeral in 1998, and for many years hosted the Frank Sinatra Celebrity Invitational Black Tie Gala.

"If he loved you, he worshiped the ground you walked on," Dreesen said. "In a lot of ways, he was like a father to me. I didn't have a father that really cared that much where I was and what I did. But Frank would give me advice and counsel and then he was a buddy in a lot of ways. I thought the world of him."