After a whirlwind east coast trip, the singer – who has been busy promoting her latest album A.K.A. – returned to Los Angeles earlier this week to finish her latest film The Boy Next Door. According to a source, Smart was on hand while she worked.
"He was there all night," the source says of the nighttime shoot. "They were loving together. [They were] very friendly and seemed good."
To those close to them, the friendly meeting isn't a surprise. When their breakup went public, a close friend told PEOPLE that Smart and Lopez would remain close. And that he would possibly continue to see Emme and Max, 6, Lopez's twins with ex Marc Anthony, periodically.
"The kids adore Casper. They have a great dad in Marc and know who their dad is, but they enjoyed being with Casper," the friend said. "It was not a bad breakup so there is no reason why they can't see Casper in the future."
As for Chmerkovskiy, he and Lopez were seen getting cozy at Shrine nightclub at the Foxwoods Casino on June 21 after her performance at the resort. Despite the outing, the source insists the two, who have denied dating rumors, "are just friends."
Lopez, who recently finalized her divorce from Anthony, met Chmerkovskiy through mutual friend Leah Remini and her DWTS partner Tony Dovolani.