John Mayer and Jennifer Aniston
Tzirel Kaminetzky; Lester Cohen/WireImage
, showing no outward signs of grief over her breakup
with John Mayer
, got a pleasant surprise this week when she ran into Friends
pal Courteney Cox
at an L.A. restaurant.
"It was a pretty amazing scene. Jen was sitting at a table inside and then suddenly Courteney Cox walked in," says a fellow diner at the Sunset Towers hotel's restaurant Thursday night. "They were pretty surprised and excited to run into each other."
Both appeared to be having business meetings over dinner, the diner says.
"Jen looked incredible," says the diner. "Let me put it this way, it made me doubt the breakup story, because there is no way she was blue in any way. She was really happy ... There was no hint of any problems."
Since the breakup, Aniston, 39, and Mayer, 30, have settled back into their separate lives on different sides of the country, multiple sources tell PEOPLE.
Aniston has been spending time at her home in the Hollywood Hills, where she was visited several times by friend and yoga instructor Mandy Ingber.
Mayer, after arriving in New York on Thursday morning on a break from his current tour, kept an even lower profile. He is due back on tour in Charlotte, N.C., on Aug. 19.
The couple, who had been dating since April, split mutually, according to a friend of Mayer.
"They were going in different directions," says the friend. "He's at the height of his career and very focused. Different things are important to them both right now."
Reporting by BRYAN ALEXANDER and MARY MARGARET