Justin Theroux and Jennifer Aniston attend the Hoyle Jackson denim launch in New York City on September 15, 2011
09/16/2011 AT 04:00 PM EDT
and Justin Theroux stepped out in style Thursday night.
The live-in lovebirds
popped into Bloomingdale's 59th Street in NYC for the launch of Hoyle Jackson denim, where they supported Aniston's stylists Clare and Nina Hallworth, the twin sister designers of the line.
Arriving just after 7 p.m., the duo
was "very social with friends and guests at the event," a source tells PEOPLE. "They were very cute. They were really just so appropriate at all times. They [looked] like a real couple."
Aniston, 42, and Theroux, 40, only stayed for approximately 30 minutes, but the insider says while they were there, the actress "was really so lovely."
"She was really low maintenance," the source adds. "[The couple] walked in together and left together … and were so relaxed."
But the outing did not end there. The duo then made their way to Il Mulino where they dined with a group of ten.
"They looked happy and were always smiling," a restaurant source tells PEOPLE. "She looked [very] good."
Reporting by JENNIFER GARCIA, LESLEY MESSER and LIZ MCNEIL