updated 03/18/2013 AT 2:40 PM ET
•originally published 03/18/2013 AT 2:30 PM ET
The trio dined at Grill Royal, a hot spot for celebrities in the area, where it looked like Clooney, 51, and Keibler, 33, “were together,” despite rumors of a possible split, an onlooker tells PEOPLE.
The Argo producer is in and around Berlin filming The Monuments Men while Damon, 42, is on hand to present Promised Land at the annual Berlin International Film Festival.
Keibler joined Clooney on Friday, when she arrived in Berlin with “quite a bit of luggage,” German tabloid Bild reports.
Hello Berlin!! Glad to be back!Excited to spend some time here :)
Stacy Keibler (@StacyKeibler) March 15, 2013
– Maggie Coughlan & Michael Anhalt
— People magazine (@peoplemag) August 7, 2012