The 40-year-old actress said on the Australian talk show Studio 10 that she considered dating Reynolds when they co-starred in the 1996 movie Sabrina the Teenage Witch.
"He wasn't the Ryan Reynolds that everybody knows these days," Hart said of the Deadpool star. "You can see in the clip the crazy hair."
"He was very sweet," she gushed. "I had a boyfriend at the time. We were smitten and cute. He was adorable. He was a really, really nice guy. Probably would have been a great boyfriend -- and I didn't end up with the other guy -- so maybe I should have taken a chance."
Reynolds played Sabrina's love interest Seth in Sabrina the Teenage Witch, which starred Hart as the titular character. The actress previously said on Chelsea Lately that Reynolds gave her a luxury watch on the last day of shooting.
"He was 17 and I was, like, 19. I was like, 'You're too young for me,'" she recalled, according to E! News. "So I stopped his car ... and I wasn't sure -- am I gonna get mad at him? I wasn't sure so I just grabbed him and started kissing him."
Hart, who also played Sabrina on seven seasons of the Sabrina and the Teenage Witch series, married Mark Wilkerson in 2003, and shares three sons, Mason, Braydon and Tucker, with the musician. Reynolds shares two daughters, James and Ines, with wife Blake Lively.