Sid Mark has been bringing Frank Sinatra to Philly listeners for more than 63 years. That won’t change, but in 2020, his show will.

Mark, the longtime host of Sunday with Sinatra on 1210-AM WPHT, is cutting the length of his show in half. Starting Jan. 5, it will run only two hours, from 11 a.m. to 1 p.m. WPHT will turn to rotating hosts from 9 a.m. to 11 a.m.

“I will do it as long as I possibly can. As long as the station is willing to air it,” the 86-year-old host said.

Otherwise, it will remain the same show, with Mark sharing songs and relaying stories about one of the most popular singers in the history of music. Sinatra died in 1998 at age 82, but Mark just keeps on trucking, acknowledging his preferences have changed over the years.

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“Today I sort of lean toward the ballads. ‘You And Me (We Wanted It All)’ was ’79, then ’84 ‘How Do You Keep the Music Playing?’ It varies from show to show,” Mark said. “But every single show for the last few years I’ve played a tune called, ‘The Trouble with Hello is Goodbye’ by Frank Jr … the audience almost demands to hear it every week.”

Mark might be in the “autumn of his years” as Sinatra famously sung, but he hasn’t lost the passion he had when he began hosting the show in 1957, when it was then Friday with Frank. Mark and his company Orange Productions (a nod to Sinatra’s favorite color) also continue to produce and syndicate a weekly show to nearly 100 radio stations across the country.

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Mark became Sinatra’s biggest radio booster by accident. While he was a DJ working overnights for WHAT in 1956, he played a full hour of Sinatra’s songs after a colleague failed to show up to work. Sixty-three years later, not much has changed.

Over the years, Mark shared a close personal relationship with the singer. In fact, during Sinatra’s performance at the Spectrum on Oct. 7, 1974, the legendary singer saluted Mark and thanked him for being one of his closest friends.

» READ MORE: Sid Mark keeps Frank Sinatra and his music alive

“I’ve had maybe four or five [friends] in my career, people who’ve stayed with me when things were dark; didn’t change at all when everything else changed,” Sinatra told the loud Philly crowd. “That’s the kind of man he is. I love him, and I say that publicly. I love him. He’s one of the best friends I’ve had in my life. I had a lot of friends, but about three days later, they were all gone. I ran out of money.”

“I was walking with him up the ramp as he was getting ready to go on and being introduced, and the ovation was thunderous. You could feel the pressure on your chest from the vacuum that was created,” Mark recalled. “And that’s when he turned to me and said, ‘Know something? All the other cities are like cookie sales compared to Philly.' ”

Staff writer Nick Vadala contributed to this article.