Rebecca Ferguson made a candid remark about becoming a mom in her early 20s with someone who was more than two decades her senior. "I was very young, but I started working at 15 ... I was thrown into the deep end of work, maturity and responsibility," the Silo actress told Harper's Bazaar of welcoming her first child when she was 23, in a Wednesday, February 4, interview. (The outlet notes, "While the age gap was significant, as she points out, she had long been living the life of an adult by then.") Ferguson, now 42, shares son Isac with ex-boyfriend Ludwig Hallberg, who is 22 years older than her. She dated Hallberg, a holistic therapist, for six years before calling it quits. While navigating motherhood, Ferguson's celebrity began to rise with roles in A One-Way Trip to Antibes in 2011 and the lead in the BBC series The White Queen in 2013. Florence Pugh Reflects on Defending Her Relationship With Ex Zach Braff "It happened quickly," she told the outlet of the latter opportunity. "I moved to Bruges to film it three weeks after I got the job." She landed a part opposite Dwayne "The Rock" Johnson in 2014's Hercules before starring in Mission: Impossible - Rogue Nation the following year with Tom Cruise. "He comes with this ... purpose. He's a boy who just loves playing, and offers up a safe and professional set. That's a really good balance [of qualities] to make you want to try new things," she said of working with Cruise, 63. Naturally, the role in adrenaline junky Cruise's film came with some death-defying stunts for Ferguson. "I was scared of heights, but you always have someone to jump in and take over, which means you can push yourself a little bit more - because at the last second you can always go, 'Nope!'" she remembered. Rebecca Ferguson Laurent Hou / Hans Lucas via AFP In addition to Isac, Ferguson is also a mother to daughter Saga, 7, whom she shares with husband Rory St. Clair Gainer. The Dune actress said she was pregnant with her daughter when filming 2018's Mission: Impossible - Fallout. "I would be fighting, and then I'd run off and vom in a big bag somewhere, have a mint, then run back in," Ferguson said of pulling off stunts. Though her bustling career has required her to travel and film in different countries, Ferguson has a rule that she will never be away from her family for more than three weeks at a time. "That was my No. 1 [priority]," she said. Elsewhere in the interview, Ferguson addressed having feelings for an older costar while working on the Swedish soap opera Nya Tider. She was 15 years old at the time, while her costar was more than a decade older and in a relationship with someone else. "I was madly in love with him," Ferguson confessed. "He was my first love. At that age, trying to understand emotions and the fact that he was with someone else ... it was hard. Understanding that it's not reality when you're lying there holding each other, it's just a moment and then you say, 'Cut!' Oh my God, my heart was torn out of my chest. I had to learn to put a hard skin on."