The two hit it off while on a double date with other people.
"About a year after 'Green Lantern' had come and gone and we were both single we went on a double date -- she was on a date with another guy and I was on a date with another girl -- and it was like the most awkward date for the respective parties because we were just like fireworks coming across," he told People magazine Editorial Director Jess Cagle on SiriusXM.
"We were buddies for a long time, which I think is the best way to have a relationship, to start as friends," Reynolds, 39, added.
Reynolds and Lively, 28, wed a year after "Green Lantern" premiered in 2012. The two have a 1-year-old daughter named James.