The longtime couple have been spotted working on their own projects in the recent months, with their busy schedules keeping them in separate parts of the world.
The 52-year-old actor has been filming The Monuments Men in Berlin as of late, alongside pal Matt Damon.
Keibler came to visit her beau on the set back in March but the two haven't been seen together since.
Rumors began swirling that the two had broken up after the 33-year-old beauty was seen hanging out sans Clooney on the Fourth of July at the DeLeon Tequila party in Malibu.
But according to eyewitnesses, it looks like Keibler is taking her newfound single status in stride.
A source tells E! News that "Stacy was acting like she didn't have a care in the world," and that "she was having a very good time letting her hair hang loose."
"She was definitely acting like a single lady," the source added.
Meanwhile, on that same day, Clooney appeared to be enjoying some R&R at his Italian villa on Lake Cuomo.
The former couple's last date night out was at Berlin's Grill Royal, where they were joined by Clooney's Argo coproducer Grant Heslov and Damon.
After their meal, the group spent some time at Soho House before calling it a night. A mustached Clooney was seen holding hands with Keibler, who was dressed casually in black jeans and flats.
Back in February, a smitten Keibler told E! News that she "loved" her leading man's latest accessory, his beard.
"I was a little surprised how gray it was when it come out," Clooney revealed on the red carpet. "It came out and it's gray! You're like, 'What the hell happened? I was young once but now I'm old.'"
Even though the two have remained fairly private about their relationship, Keibler did open up last year to E! News about not being in a rush to walk donw the aisle.
"That is not on my radar at all," Keibler said. "I'm definitely the girl who doesn't talk about that kind of stuff. I'm not really interested in thinking about marriage or kids at all."