George Clooney and Amal Alamuddin Attend Wedding in Cabo San Lucas
05/06/2014 AT 10:45 AM EDT
The actor, 52, took a private jet to Cabo San Lucas, Mexico, with his bride-to-be, Amal Alamuddin, on Thursday.
Sources tell PEOPLE the trip was to celebrate the wedding of Clooney's longtime pal, actor Thom Mathews.
It's not the first trip to the celebrity hot spot for the globe-trotting couple, who also visited the area during the holidays last year, along with close friends Rande Gerber and Cindy Crawford.
This time around, we know just how Alamuddin accessorized her beachwear: with a certain dazzling sparkler.
For much more on Clooney's engagement news, pick up this week's issue of PEOPLE, on newsstands now.