Rachel McAdams gave birth to her first child in April with her longtime partner, screenwriter Jamie Linden.

The 40-year-old Canadian actress described her son as "the greatest thing that’s ever happened to me, hands down," in a recent interview with The Sunday Times.

"[People say] your life is not your own anymore. But I had 39 years of me, I was sick of me, I was so happy to put the focus on some other person. I waited a long time [for motherhood]," she told the magazine.

On waiting to become a mother until she was 39, she said that was simply the way the timing played out. "And I didn’t want to do it before it was the right time," she said.

The actress, who most recently starred alongside Rachel Weisz in "Disobedience," a love story about a lesbian relationship in an Orthodox Jewish community, plans to maintain the extreme sense of privacy she has cultivated while raising her son.

Her decision is unsurprising given that she’s always stayed off social platforms and tends to keep her personal life out of the spotlight.

"I don’t even quite know how it works," she said. "I’m not a great self-promoter, I wasn’t good at selling Girl Guide cookies or Christmas wrapping paper. Knocking on people’s doors and asking for money was just not my thing," she told The Sunday Times.

She said despite the craziness of being a new mother, she’s managing.

"I have clothes on and that’s a good thing," she joked to the newspaper. "I don’t even know what I’m wearing today. The shoes are held together with glue. Isn’t that sad? I need to get a life."

"I’m having more fun being a mum than I’ve ever had. Everything about it is interesting and exciting and inspiring to me. Even the tough days -- there’s something delightful about them," she added.

Her perspective on life has also shifted, and she doesn’t rule out having more kids.

"You see everything through a particular lens: very sensitive, more open. It’s like being on an aeroplane all the time."

While McAdams is focused on motherhood, she’s also taking over screens across the world. For the October issue of The Violet Book magazine, McAdams spoke with "Disobedience" co-screenwriter Rebecca Lenkiewicz about her process when it comes to perfecting her craft.

"I have to fool myself into thinking no one’s gonna see something. So I sort of act like no one is watching, in a way," she told the magazine.

"I think that’s what’s so vulnerable about acting, is that on those days when you don’t feel confident, and there’s so many — I would say maybe 8% of a shoot I feel confident about something. The rest of the time I don’t."

She said that showcasing that vulnerability is often one of the most important traits of an actor.

"The sensitivity of an actor is often the very thing that you want to watch -- that rawness -- like, I don’t know what I’m doing, I don’t know exactly how to say this line. It’s those moments when people stumble, those really organic moments that everybody remembers, I think," she told The Violet Book.

She channeled this vulnerability going into "Disobedience," telling The Sunday Times that she had, "some trepidation," about her role in the film.

On her love scene with Weisz , she shared, "[That scene] was so integral to the plot. My character was so penned in that there was something so freeing about being that literally and metaphorically naked … It took us a minute to get started, but it wound up being a really wonderful day."

McAdams has evolved as an actress throughout the years, playing roles in everything from the 2016 Oscar-winning picture "Spotlight" and 2015 drama "Southpaw" to romantic dramas like "About Time" and "The Notebook."

In 2017, she spoke to Vanity Fair about the alleged sexual harassment she experienced from screenwriter James Toback.

Because of the #MeToo movement, she told The Sunday Times that "I’m feeling better about the world that young actresses are coming into."