The 35-year-old actress said in the August issue of Marie Claire that the secret behind her happy marriage to Timberlake is their similar beliefs and interests.
"We have similar values; we believe in honesty, loyalty," Biel told the magazine. "We like to have fun. We like a lot of the same things."
"Also, in the business, we're all very career-oriented, and you have to be a little selfish," she added.
"I understand that about my peers -- about being focused and driven -- and if you can find that and someone who shares the same values as you, it's like: Score!"
Biel and Timberlake married in Fasano, Italy, in October 2012 after more than five years of dating. The couple welcomed their first child, son Silas Randall, in April 2015.
"[Fatherhood] changes everything," Timberlake said in an interview with "Today" in October.
"It's crazy. There's new appreciation for both of them -- her and him. It's humiliating and it's humbling at the same time."
Biel will next star in USA Network adaptation of the Petra Hammesfahr novel "The Sinner."
She told E! News in April that Timberlake has done nothing but support her "dark" role in the forthcoming show.
"He supported me from the very beginning," the actress said. "He's excited because I'm excited. He's just been a wonderful partner. Completely supportive, even though it is dark."
"I have to really put myself out there in a way that feels a little scary and is a little exposing," she added. "He understands because he's an actor and that's what we do. He's just been a great partner in all of it."
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