The actor was caught on camera gazing at Lopez while she threw her head up in frustration. Affleck, 48, was reportedly driving Lopez, 51, to her home.
The couple is said to be spending every night together.
"Ben and Jen are spending almost every night together when they’re not working," an insider told Us Weekly earlier this month. "They plan on moving in together very soon."
The two have even begun house hunting, according to the outlet.
"The past few months have been a real whirlwind," another source said. "They’re well aware some cynics still look at it as a big flashy attention grab and roll their eyes at the speed of it all, but it doesn’t faze them one iota. They’re fully committed to taking the next steps and spending the rest of their lives together."
Lopez and Affleck rekindled their relationship after the singer and her fiancé, Alex Rodriguez, called it quits in April.
"We have realized we are better as friends and look forward to remaining so," the couple said in a statement at the time.
Affleck and Lopez were previously engaged for roughly two years. The two split in 2004 and Affleck went on to marry actress Jennifer Garner in 2005. The pair – who share three children together – divorced in 2018.
Lopez recently opened up about her album "This Is Me… Then," which included songs written about her then-romance with Affleck. "Loving You," "All I Have" and "Dear Ben" were all inspired by the "Gone Girl" actor.
"That was a moment. When you go back and hear that, you hear the purity and the love there," Lopez told Apple Music 1’s Ebro Darden. "And I think that’s why people went back as they saw different things happening in my life now and they go, ‘Wow, really?’ And I think it gave people hope. … Some things do last forever."