Their night out? A trip to see a solo show by McDaid's Snow Patrol bandmate, Gary Lightbody.
Cox, picked as Aniston's maid of honor, was initially believed to have joined her for the trip to Bora Bora, along with Aniston's new husband, Justin Theroux, and Jason Bateman, Jimmy Kimmel and their families.
Courteney Cox's Changing Looks!
However, on Saturday, McDaid, 39, Tweeted that he and Cox would be attended Lightbody's show at the Largo in L.A.
He preceded this with the slightly more cryptic Tweet, "Nothing is what it seems!"
So while Aniston, 46, and Theroux, 44, were snapped stepping onto one of their favorite spots, Cox, 51, was spotted in the audience at Largo.
The moment was captured by a fellow concertgoer, who managed to snag a selfie with the Cougar Town star.