With Affleck hailing from Massachusetts, the Justice League star was naturally all smiles while cheering the Red Sox, sporting team apparel and chatting with fans in the stands.
His ex-wife, Garner dressed casually and looked comfy while sitting with fellow actress, Angela Bassett. Affleck's brother Casey was also attending the game.
The rare, joint sighting comes after just days reports broke that Garner, 46, is now dating businessman John Miller, CEO of CaliGroup, which owns Miso Robotics and a chain of 50 CaliBurger restaurants. While the romance is fairly new, the two met through mutual friends and have been on a few dates as revealed by sources close to the pair.
"They've been together six months — and it's getting pretty serious," a source told Us Weekly. A second added, "Jen brings out the best in John, and he is the happiest he has probably ever been. It's a loving, healthy relationship."
Another source went on to reveal that the two are at similar places in their lives as Miller is also recently divorced and has two children around the same age as Garner's daughters.
As for Affleck, the 46-year-old is focusing on himself after breaking up with Playboy playmate, Shauna Sexton, and was released from a rehab facility where he was being treated for alcohol addiction. Shortly after, he released a statement addressing his progress.
"This week I completed a forty day stay at a treatment center for alcohol addiction and remain in outpatient care," he wrote. "The support I have received from my family, colleagues and fans means more to me than I can say. It's given me the strength and support to speak about my illness with others."
He went on to share how battling any addiction is a lifelong and difficult struggle.
"Because of that one is never really in or out of treatment. It is a lifelong commitment. I am fighting for myself and my family," he continued. "So many people have reached out on social media and spoke about their own journeys with addiction. To those people I want to say thank you. Your strength and courage is inspiring and is supporting me in ways I didn't think was possible. It helps to know I am not alone.0comments
As I've had to remind myself, if you have a problem, getting help is a sign of wisdom and strength, not weakness or failure. With acceptance and humility, I continue to avail myself with the help of so many people and I am grateful to all those who are there for me. I hope down the road I can offer an example to others who are struggling."
Soon after his release, the former couple officially finalized their divorce following their separation in 2015.