Held on the same evening but at a different landmark (also kept a secret until the last minute), it will feature nearly 350 folks dressed head to toe in black.
Feel silly going B&W for supper? Or paying $50 or more for dinner? Blanc, a for-profit enterprise, charges $68.50. For Noir, the check is $50, with revenue raised beyond expenses going to the food charity Philabundance.
Well, now there's Dîner en Sweatpants.
Designed as a let-it-all-hang informal party for the rest of us schlubs, the free event will rock on at Clark Park in University City from 5:30 to 8:30 p.m.
Dress however you like, bring hangout food - or buy munchies at the Clark Park Farmers Market or from one of the two lunch trucks that will be there.
Music will be provided by Huey West.
"He's a busker I've seen in Rittenhouse Square, and he's amazing," said Dîner en Sweatpants creator Rachel Robbins. "He'll play acoustic guitar and banjo."
Robbins, an event organizer for local firm TicketLeap, which is putting on the event, said she came up with the idea only a few weeks ago.
"Once we heard Dîner en Blanc was sold out, I thought it would be a good idea to a have a fun casual event where people could just come by and hang out," Robbins said in a phone chat.
"When I told a friend . . . she said, 'That sounds like Dîner en Sweatpants'! I loved the name, so we just ran with it."
Robbins, who announced the event two weeks ago, said she expected no more than 25 people to show up.
"We thought we'd be happy with 25. Fifty would be awesome," she said. "But more than 100 have RSVP'd."
For Robbins, all three dinners are expressions of community spirit.
"They show people that it's possible to build community through events."
Robbins said she was nonplussed by Noir founder Chris Nowaczyk's description of their dinner as a rebellion.
"I expected it to be more different [than Dîner en Blanc]. But it's pretty much the same thing," she said. "Except they'll be wearing black. . . . That's why I wanted to make ours totally different."
Dîner en Blanc cohost Natanya DiBona said she was tickled by the latest event.
"I honestly feel the fact that these other two events are highlighting and celebrating public space in the community is wonderful. It's beautiful that they are calling attention to the city," she said by phone.
"And the sweatpants thing is just funny."
Dîner en Sweatpants
5:30-8:30 p.m. Thursday (rain date next Thursday) at Clark Park, 43d Street and Baltimore Avenue.
Information: 877-849-5327 or http://events.ticketleap.com/diner