Jennifer Aniston can’t resist the charms of former flame John Mayer.

Now Magazine claims Jen has been secretly hooking up with her musician ex for clandestine sex sessions at the Four Seasons Hotel in New York — where the 40-year-old actress is filming the upcoming comedy The Hangover alongside actor Bradley Cooper.

John, 31, flew from Los Angeles disguised to avoid paparazzi attention as he went up to Jen’s penthouse suite for a romantic evening for two last month, the tabloid claims.

“John flew to New York in the middle of August for 48 hours to spend time with Jen while she was filming,” says a spywitness. “He managed to give the paparazzi the slip and the couple spent time talking. John left convinced it’d be worth giving things one more shot.”

The insider adds, “Of course, talking wasn’t all they did; their relationship’s always been based on great sex. Jen says she hasn’t met a guy who’s had this effect on her before – John’s the best lover she’s had. That’s why she’s glad to go back.”

Friends say John’s been calling the former Friends star, who he’s dated on and off for 18 months, pleading with her to take him back.

“John’s previewed his new recordings for Jen, where he’s pouring his heart out about their relationship. That’s helping them to figure out if they have a future together.”