The 29-year-old actress is excited about what her future with fiancé Jason Sudeikis holds and is looking forward to having a "little party" of kids with the 'Horrible Bosses' star - who she thinks will make a great father.
She said: "[I] can't wait for children. I'm open-minded about how many, but three, which I love, is like a little party. I am not trying to have kids now - there's no strict plan for anything in my life.
"What happens, happens. [Jason's] so good with kids ... I've never before experienced looking at someone and thinking, 'That's who I want to raise a child with.' "
Olivia first met Jason, 37, on the 'Saturday Night Live' finale in 2011 and the brunette beauty was convinced she wasn't a "contender" for the funnyman.
She continued to the April version of America's Marie Claire magazine: "He was so cool, so funny - I was such a fan of his and had always fancied his speed and his intelligence.
"He's a brilliant actor with a brain like lightening. I thought, 'I'm not beautiful enough or his type.' I couldn't wait to sit down and hear him talk."
The 'Deadfall' actress was previously married to Italian filmmaker and musician Tao Ruspoli, who she wed when she was 19, and although the marriage - which ended in divorce in 2011 - caused her heartache, she is "grateful" for the journey which led her to her current boyfriend.
She recalled: "I had grown up with Tao; we had just drifted. I felt I had something to prove. If you fall off a horse, you get back up. I am not a quitter.
"I hung on for as long as possible, until it was more hurtful to stay ... I'm so grateful for the pain and the heartbreak. It gave me the courage to leave and brought me the great love of my life."