Get ready for BJ the DJ.

Billy Joel dropped by “The Tonight Show Starring Jimmy Fallon” Wednesday night to announce that the Billy Joel Channel will return to Sirius XM Radio starting Jan. 15.

Joel told Fallon he will be more involved in this incarnation and that it will be “not just me, but stuff I like,” adding that he may also show up as a disc jockey on the channel, as BJ the DJ, doing impressions of New York DJ legends Cousin Brucie and the late Scott Muni.

He and Fallon also discussed their plan to take over WLNG 92.1-FM in Sag Harbor some night where they would perform their favorite doo-wop and rock classics unannounced, an idea hatched at a party at Howard Stern’s house where Joel and Fallon sat around a piano all night.

Joel, 66, also announced that he will add another show to his record-setting run at Madison Square Garden on July 20. However, sales information hasn’t been released yet.

Joel kicks off the third year of his Madison Square Garden residency Thursday night and he invited Fallon to perform a song with him. Then they performed the Rolling Stones’ “Beast of Burden” together, with Fallon adopting a Mick Jagger accent. (The studio audience was also treated to an impromptu a cappella version of “The Longest Time,” featuring Joel and his band, Fallon and the show’s other guest Oscar winner J.K. Simmons.)

Joel, who also performed a stunning, eight-minute-plus version of “Scenes from an Italian Restaurant” on “The Tonight Show,” said that he has been surprised by the demand for his Garden concerts.

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“I didn’t know it was going to go this long,” he said. “And if there’s still a ticket demand, I’m going to keep playing there.”

“You won’t stop,” Fallon told him. “It’s the most fun night.”

“It may go on for the rest of my natural life,” Joel said.

Fallon suggested that the next generation of Joels, his daughters Alexa Ray, who just turned 30, and Della Rose, who will turn 5 months old next week, could carry on the family business as a group.

“That’s not a bad idea,” joked Joel, adding that Alexa, who recently wrapped up a run at the Café Carlyle, loves to harmonize with him and that Della Rose is already showing interest.

“She’s already digging music I can tell,” Joel said.