When Britt Lower signed on to star in Netflix’s gripping new thriller I Will Find You, she had no idea she would also gain the sister she had always longed for. The 40-year-old actress, best known for her role in Severance, formed a deep and genuine bond with her co-star Erin Richards during the five-month production in Toronto. Their off-screen friendship became so strong that it naturally infused their on-screen sisterly dynamic with authenticity and emotional depth.

In the Harlan Coben adaptation, Lower plays Rachel Mills, the fiercely loyal sister of Cheryl (Richards) and the ex-sister-in-law of David Burroughs (Sam Worthington). After David is wrongfully convicted of murdering his young son Matthew, Rachel discovers evidence that the boy may still be alive. She teams up with David to uncover the truth, driven primarily by her unwavering love and loyalty to her sister. Lower revealed in an exclusive interview with People that portraying this sisterly connection came naturally because of the real-life bond she developed with Richards.

“I don’t have a sister in my real life, but I’ve always wanted one and I felt really kindred with Erin,” Lower shared. “We had a great time bonding.” Their friendship extended far beyond the set. The two actresses spent quality time together outside of filming, even celebrating Easter Sunday with each other’s families. “We spent an Easter Sunday together,” Lower recalled warmly. “So it was really kind of a sweet, pretending we were sisters for the whole time.”

This real-life closeness proved essential to the story. While parental relationships and the central mystery drive much of the thriller’s suspense, the sisterly bond between Rachel and Cheryl forms its emotional core. Lower explained that Rachel’s decisions throughout the series — including her choice to approach David first rather than going directly to her newly married and pregnant sister — stem from a deep protective instinct. “It’s really at the core of Rachel’s drive,” she said. “The whole series is her love for her sister, her loyalty to her family.”

Lower praised the collaborative environment created by Coben, whose 2023 novel served as the foundation for the series. She described having access to the author’s insights as a “treasure trove” that helped the cast step fully into their characters’ perspectives. “You not only have his book, the resource of him and where these ideas came from in the first place, but you also have the generosity of Harlan Coben,” she noted. This support allowed the actors to explore the nuances of their roles and bring the characters to life as fully realised people rather than just plot devices.

The strong off-screen relationship between Lower and Richards also enhanced the on-screen chemistry, making the sisterly interactions feel lived-in and believable. Their friendship helped ground the high-stakes thriller in genuine emotion, giving audiences someone to root for beyond the central mystery of Matthew’s fate.

For Lower, the experience was particularly meaningful. As someone who has spoken about the importance of chosen family in her own life, finding a real connection with Richards during production added an extra layer of personal significance to the project. The bond they built translated into powerful performances that elevate the series beyond a standard crime thriller.

I Will Find You has quickly gained attention as one of Netflix’s standout new releases, thanks in part to its compelling characters and the authentic relationships at its heart. Lower’s portrayal of Rachel — driven, protective, and emotionally complex — has been praised by viewers and critics alike. Her chemistry with both Worthington and Richards anchors the story, making the audience invested not just in solving the mystery, but in the personal journeys of the characters.

The series marks another strong performance for Lower following her breakthrough in Severance. Her ability to convey both vulnerability and steely determination makes Rachel a compelling protagonist. Meanwhile, the friendship she formed with Richards stands as a testament to how shared creative experiences can create lasting personal connections in the entertainment industry.

As I Will Find You continues to stream on Netflix, audiences are discovering not only a taut, suspenseful thriller but also a story enriched by the real emotional bonds formed behind the scenes. Lower and Richards’ sisterly connection serves as a beautiful reminder that sometimes the most meaningful relationships are the ones we find unexpectedly while doing what we love.

In the competitive world of prestige television, it is these authentic human connections — both on screen and off — that often make the difference between a good series and a truly memorable one. For Britt Lower, I Will Find You gave her more than just another compelling role; it gave her the sister she had always wanted.