Ex allegedly pranks former beau by listing his cell phone under starry new Hamptons hotspot

They’ve got some hang-ups in the Hamptons!

Page Six hears there were some crossed communications at the newly opened La Goulue Sur Mer in Southampton when eager diners tried to snag reservations — and were shocked to reach a random, annoyed man when they dialed the listed number.

“He said he was getting nonstop calls for the hot new restaurant,” a source spilled, adding that the guy who answered believes a recent ex-girlfriend — or one of her salty friends — had swapped his number into the restaurant’s listing as petty payback over their split.

“They just broke up three weeks ago and he was saying he thinks her or one of her friends did it,” a caller who wound up chatting him up told Page Six.

The dude did not return Page Six’s request for comment.

Co-owner Anthony Punnett, who just opened the space on July 2 with Joseph DeCristofaro, confirmed the mix-up, telling us, “There was a lot of confusion around it during the first week.”

But Punnet tells us they have updated the number on OpenTable, and are working to fix the number that comes up via Google.

Despite some phone issues, there were plenty of bold-faced names who managed to snag a reservation.

A spy tells us they saw “The Blue Lagoon” actress and famed Calvin Klein model Brook Shields, 60, sitting with her husband at the bar.

Another tells us they saw “Top Chef” host Padma Lakshami, and “Man Repeller” founder Leandra Medine Cohen.

We hear the French brasserie, featuring red banquettes and Parisian chandeliers, pays tribute to the NYC original that opened in 1972 and is a mainstay of the Upper East Side social set.

Jean Denoyer, who founded the restaurant, has given the new Southampton spot his blessing.

The name comes from a famed Moulin Rouge performer from the early 1900s who was painted several times by Henri de Toulouse-Lautrec.

There are a number of new spots in the Hamptons this summer.

Swifty’s has opened at the Hedges Inn in East Hampton under the same management as the Colony in Palm Beach, while the clubby Mary Lou’s has opened in Montauk, and Gigi’s has taken over the main dining space at Gurney’s.