The duo, dubbed "Bennifer" by fans during their engagement over a decade ago, recently took their travels to Miami, Fla. where an onlooker spotted them working out together at a gym.
According to a source, the singer and actor weren't hiding their rumored romance as one person spotted them sharing "a kiss between sets," Entertainment Tonight reports.
Lopez and Affleck's outing reportedly took place at Anatomy Fitness in Miami. "They went to do their workouts with separate trainers, but were not trying to hide their relationship by any means," the insider dished.
While the two were each working on their fitness, they were spotted "hugging" and "being playful together." The source added that it was "clear to everyone that they have intense chemistry and were having fun together."
"They were having a good time," the source added. "Jennifer works out every day and it's part of her routine and it seemed like Ben really wanted to be there too with her."
The eyewitness concluded that the two appear to be in the "honeymoon phase." Lopez and Affleck's alleged rekindled romance has been the talk of Hollywood, with fans and stars weighing in with an immense amount of support for the couple to become official once again.
What's more, the "Argo" star was also reportedly spotted donning a unique watch that the "Hustlers" star gifted him back in 2002. Affleck wore the original watch while filming the "Jenny From the Block" music video. It features a thick silver chain and a thin face.
Lopez and Affleck were engaged in 2002 but split in 2004. They co-starred in the films "Jersey Girl" and "Gigli" together.
In photos obtained by the U.K.'s DailyMail in early May, the two were seen driving together in an SUV with Affleck at the helm and Lopez riding in the passenger seat. The Oscar-winner has a home in Big Sky, Montana. They later flew back to Los Angeles on a private jet together. In recent weeks, Affleck has also been spotted arriving at and leaving from Lopez's Bel Air mansion.
Fox News' Jessica Napoli contributed to this report.