Ben Affleck spends some family time with his two youngest children while running errands in Los Angeles

It was announced this week that Killing Eve's Jodi Comer may be joining his upcoming medieval revenge drama, also starring Matt Damon.

Ben Affleck didn't betray much excitement about the new development as he ran errands in Los Angeles' Brentwood neighborhood on Friday.

The 47-year-old Gone Girl actor stepped out in a simple set of sweats as he was joined by his two youngest children, Seraphina, 10, and Samuel, seven.

Family outing: Ben Affleck, 47, was seen running errands around LA's Brentwood neighborhood on Friday with his two youngest children, Seraphina, 10, and Samuel, seven

Family outing: Ben Affleck, 47, was seen running errands around LA's Brentwood neighborhood on Friday with his two youngest children, Seraphina, 10, and Samuel, seven

Ben covered up his muscular torso in a burgundy zip-up hoodie that read 'DETROIT' across the chest, while wearing a peach-colored T-shirt underneath.

He kept the hood up and partially obscured his face and dark beard.

The Shakespeare In Love actor also had on a pair of black Nike track pants, which he mixed with simple navy blue trainers.

Broad shoulders: Ben covered up his muscular torso in a burgundy zip-up hoodie that read 'DETROIT' across the chest, while wearing a peach-colored T-shirt underneath

Broad shoulders: Ben covered up his muscular torso in a burgundy zip-up hoodie that read 'DETROIT' across the chest, while wearing a peach-colored T-shirt underneath

No fuss: The Shakespeare In Love actor also had on a pair of black Nike track pants, which he mixed with simple navy blue trainers

No fuss: The Shakespeare In Love actor also had on a pair of black Nike track pants, which he mixed with simple navy blue trainers

Blank face: Brad looked stone-faced and had his eyes down at his phone while on the move

Blank face: Brad looked stone-faced and had his eyes down at his phone while on the move

Ben was joined on his walk by Samuel and Seraphina, both of whom looked similarly casual.

Samuel sported a gray and maroon baseball shirt with charcoal shorts and a blue backpack.

Seraphina sported a fuzzy backpack adorned with tiny stuffed animals. She also had on a teal shirt with black leggings and a black sweatshirt tied around her waist.

Though he was on his own on Friday, Ben regularly spends time with all three children (including his oldest, 13–year–old Violet) and his ex-wife Jennifer Garner, 47.

Since the couple's divorce announcement in 2015, they've been spotted together many times attending church as a family.

Ben and Jennifer have also come together as a family for their children's baseball and soccer matches. 

Low-key look: Ben was joined on his walk by Samuel and Seraphina, both of whom looked similarly casual. Samuel sported a gray and maroon baseball shirt with charcoal shorts and a blue backpack

Low-key look: Ben was joined on his walk by Samuel and Seraphina, both of whom looked similarly casual. Samuel sported a gray and maroon baseball shirt with charcoal shorts and a blue backpack

Playful: Seraphina sported a fuzzy backpack adorned with tiny stuffed animals. She also had on a teal shirt with black leggings and a black sweatshirt tied around her waist

Playful: Seraphina sported a fuzzy backpack adorned with tiny stuffed animals. She also had on a teal shirt with black leggings and a black sweatshirt tied around her waist

Though Ben looked stone-faced and had his eyes down at his phone for much of the morning outing, he may have been excited about the news of his proposed film collaboration with Matt Damon.

The two have co-written a screenplay with writer and director Nicole Holofcener based on the non-fiction book The Last Duel, about the last officially sanctioned trial by combat that occurred in 14th Century France.

Ben and Matt would star in the film as the Norman knight Jean de Carrouges and his squire Jacques Le Gris, though it hasn't been revealed who is playing which part.

Reunited: Ben recently got good news about the future of The Last Duel, a medieval revenge drama he co-wrote and will co-star in with Matt Damon; pictured together in 2016

Reunited: Ben recently got good news about the future of The Last Duel, a medieval revenge drama he co-wrote and will co-star in with Matt Damon; pictured together in 2016

The real-life story involved Carrouges charging that his wife had been raped by his squire Le Gris.

After the two are ordered to have a battle to the death to determine whom has been chosen by God, Carrouges tries to appeal the decision. If he should die in battle, his wife will also be burned at the stake for supposedly lying about her rape.

Shortly after she won an Emmy on Sunday, Killing Eve actress Jodie Comer was announced as in talks for the role of Carrouges wife in the film.

The movie is expected to be directed by Ridley Scott, though it has yet to get the official green light.

Starpower: Shortly after her Best Actress win at the Emmys on Sunday, it was revealed that Killing Eve's Jodie Comer was in talks to play a major role in The Last Duel; pictured Sunday

Starpower: Shortly after her Best Actress win at the Emmys on Sunday, it was revealed that Killing Eve's Jodie Comer was in talks to play a major role in The Last Duel; pictured Sunday

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