Before Howard Stern’s return to the airwaves was unexpectedly postponed by an unnamed family emergency this week, the famed shock jock was spotted at a historic SiriusXM event in the Hamptons, according to sources.

Spies said that Stern was at Metallica’s unprecedentedly intimate show at the Stephen Talkhouse in Amagansett last Thursday.

Insiders told Page Six that, “Stern enjoyed the concert with wife Beth as well as one of his daughters and her husband, staying the entire show and singing along all night.”

Also at the special VIP performance — where the metal gods launched their Maximum Metallica channel — was music legend Paul McCartney, “Rocky” icon Sylvester Stallone, “Back to the Future” star Michael J. Fox, Bravo host Andy Cohen, “SNL” star Colin Jost, filmmaker Ed Burns, wrestling star Chris Jericho, Maria Menounos and Red Hot Chili Peppers drummer Chad Smith.

Comedian Heidi Gardner, 42, was seen rocking out, sources told Page Six, the same day that news broke that she was leaving “Saturday Night Live” after eight seasons amid the NBC sketch show’s shake-up.

Concertgoers sipped on cocktails and enjoyed ice cream from a Carvel truck.

The historic gig is being broadcast this week on Metallica’s SiriusXM channel. Stern is expected back on the air Monday.

His contract with the broadcaster is due to end this year.

Metallica drummer Lars Ulrich had announced the band’s SiriusXM channel on Stern’s show last month, and Stern told him, “Wow, that’s a hell of an announcement… Welcome to the family. I’m glad you guys are on SiriusXM.”

During their Amagansett gig, the band played hits including “Master of Puppets,” “Enter Sandman” and “Fade to Black” as well as a cover of “Crazy Train” as a tribute to the late metal pioneer Ozzy Osbourne.