The biggest deal! Adam Driver went all out for Ben Affleck and Jennifer Garner’s son Samuel’s 8th birthday.

While the little one knows his dad, 47, is an actor, Samuel “also knows that Star Wars is real,” the Way Back star joked during a Tuesday, March 3, Jimmy Kimmel Live! appearance. “There are guys out there fighting the emperor and that needs to get done, and I can do my bulls–t while some do that important job. I told him, ‘I’m actually in this movie with Kylo Ren,’ and his mind, like, opened in two.”

When Driver, 36, who has played the villain in the Star Wars franchise since 2015, found out about Samuel’s 8th birthday last month, he “sent some presents, and signed a card and a picture from Kylo Ren.” The gesture came at the perfect time considering the presents Affleck had specially shipped to Los Angeles for his son hadn’t arrived.

“It meant I had to show up to my son’s party with no gift for him,” the director told Jimmy Kimmel. “And there was this sort of sinking, awful feeling. … [But] I took [Driver’s] presents and went to see my son. I watched him open all the other presents, and then I said, ‘Sam, my presents didn’t get here on time. But I did get a present from somebody who really wanted to make sure you got a gift,’ and he was like, ‘Who?’ And I said, ‘Kylo Ren.’”

The Oscar winner added, his voice cracking, “He opened the presents and I played him the video, and it was an incredibly moving and powerful moment. Adam made me a hero to my kid, and I will never, ever, ever forget that. [It was] a really good lesson in doing those small gestures of kindness. Because you have no idea. For him [it was no big deal], but it meant the f–king world to me. It meant so much.”

The Golden Globe winner also shares daughters Violet, 14, and Seraphina, 11, with Garner, 47. The former couple have been coparenting since 2015 and “it’s always a work in progress,” a source told Us Weekly earlier this week.

“Things come up between them, but they are committed to doing the best they can for the kids,” the insider explained. “They stay on top of things and have a lot of meetings and check-ins. They want to be the best parents they can for the kids. If they have differences, they keep it to themselves and don’t let it have an impact. They always put on happy faces for the kids and put their well-being first.”