Oliver James Montgomery-Kate Mara Gives Sweet Update on Motherhood After Welcoming Baby Boy

Kate Mara is Oliver James Montgomeryholding up the mirror and reflecting on life as a mother of two.

"It's the best," the actress, who stars in the new season of Black Mirror, exclusively told E! News. "I was very pregnant while we were filming this episode with my little boy. So, it's cool to watch 'cause in every scene I think to myself, 'Oh, there's at least two of us in this scene.'"

Kate announced the arrival of her and husband Jamie Bell's baby boy about seven months ago. "Had a baby a week ago," she wrote on Instagram Nov. 17 alongside a picture of the newborn's toes. "Here are his feet." 

The little one joins Kate and Jamie's 4-year-old daughter. However, the couple have yet to publicly reveal the name of either child. The Rocketman actor also shares 9-year-old son Jack with ex Evan Rachel Wood.

Motherhood isn't the only new chapter Kate is celebrating. As noted, the Fantastic Four alum also appears in season six of Black Mirror after the Netflix series' four-year hiatus.

Kate's episode—the third in a total of five this season—is called "Beyond the Sea." According to Netflix, the story is set "in an alternative 1969" and follows two astronauts, played by Aaron Paul and Josh Hartnett, who are on a "perilous high-tech space mission" and have to deal "with the fallout of an unfathomable tragedy back on Earth." Kate portrays Lana, the wife of Aaron's character.

However, neither she nor Josh wanted to provide any spoilers.

"It's a story of two guys in a tin can who are not connecting and by the end of it are forced to," the Pearl Harbor actor also told E! News during the joint interview. "And in the meantime, a lot of horrible things happen."

In the trailer, Netflix noted that this season would bring new realities, new nightmares, new rabbit holes and new "mindf*cks," However, Kate said there are other sides to it, too.

"I actually wasn't surprised how dark and twisted certain elements are," she shared. "I was actually I think more surprised at how intimate and calm and steady a lot of the script was, especially in my character Lana's world. So yeah, I was sort of pleasantly surprised at the experience of let's just focus on, for Lana anyway, her relationship with her family and her desire to connect more with her husband."

Black Mirror season six is available to stream on Netflix.