Aniston walked the red carpet a good five minutes before Vaughn, and the pair never got within 25 feet of each other.
Still, both signed autographs for some of the hundreds of screaming fans and, once inside the theater, posed for group pictures with costars Jon Favreau and Joey Lauren Adams and director Peyton Reed.
Aniston, looking tan and relaxed, told reporters of Vaughn, "He's a professional. He's unbelievably good at his job. I didn't feel compromised as an actor because my costar was going off and doing his thing."
Vaughn, who is also a producer and writer of The Break-Up, was in equally high spirits. "I feel great," he said. "The response has been so good, the movie's very funny, and it also has some real moments in it. I'm excited to be out tonight."
The couple, who got to know each other while making the film, have never confirmed anything more than an off-screen friendship, although Vaughn told Oprah Winfrey this month that Aniston is "just really smart and funny and easy to be with."
Musing on their future, he said, "No, I have not talked about having kids with Jennifer," he said, and then joked, "First we have to have the $8 million wedding."