Justin Theroux and Jennifer Aniston attend the Hoyle Jackson denim launch in New York City on September 15, 2011
10/05/2011 at 01:00 PM EDT
At least one thing is working right in Washington, D.C.: Jennifer Aniston
and Justin Theroux's hot new romance
The new couple
got cozy over dinner Monday night at Fiola, a restaurant on Pennsylvania Avenue, where the pair were "very, very cute together," a source tells PEOPLE.
And Jen and Justin were not alone. They were joined for the meal by a Lifetime executive, as well as Jeanne Tripplehorn and Patricia Clarkson, all of whom were involved with the TV channel's film anthology, Five
(premiering Oct. 10), for which Aniston directed
one of the segments.
Calling Aniston, 42, and Theroux, 40, "very cutesy," the witness also says, "They were paying attention to each other. They ate the same thing."
Their dinner order? A salad, plus the tagliatelle with Alba white truffle, a $65 pasta entrée. For dessert, they ordered the bonboloni pastry made with ricotta cheese.
"They loved those," says the source, who was "surprised – in a good way – they would eat all that."
As for the dinner party, which went on until about 11 p.m., "They had a great time, all of them. They were laughing. It was like a group of friends," says the source.
But most eyes in the place were focused on Jen and Justin
, who had been "talking and smiling to each other, like any couple would do," says the source.