“Muppets” star Jason Segel was revealed as a dark-horse sex symbol at Lower East Side hot spot Sons of Essex on Monday night. The usually shaggy comedy actor was “swarmed by women,” witnesses said, at an after-party for his new movie, “Jeff, Who Lives at Home,” co-starring Ed Helms. “He’s actually better looking in person,” cooed one spy. “And he was wearing a suit so he was more put together than usual.” There were so many ladies “vying for Segel’s attention” that he “never even made it past the front bar to a reserved table in the back,” we’re told. The source added that admirers asking for photos included “tall, leggy models” at the Hollywood Reporter and Fiji water-sponsored bash. Susan Sarandon, meantime, was spotted hanging out at a secluded table in a slinky black number. Other guests included “30 Rock” star Judah Friedlander, Samantha Mathis, Tara Subkoff and director Mark Duplass. Segel said last week that he’s decided not to star in — or write — a planned “Muppets” sequel.