Christopher Reeve's children honor him at 'Super/Man' documentary premiere

The late Christopher Reeve's children stepped out together for the premiere of "Super/Man: The Christopher Reeve Story," which explores the legacy of their beloved father.

The documentary follows Christopher Reeve's life as he became the iconic "Superman" character and after he was paralyzed in a near-fatal horse-riding accident in 1995. It also reveals how much of a family man Reeve was as a father and husband. The film also includes his relationships with actors Robin Williams, Susan Sarandon, and Glenn Close.

Reeve's three children, Alexandra Reeve, Matthew Reeve, and Will Reeve, an ABC News correspondent, told "Good Morning America" on Wednesday at the premiere that the film is a tribute to their father's legacy and the lasting impact he had on who they are today.

"My dad was an incredibly intense person. He did nothing at half effort," Alexandra Reeve said. "And I think all three of us at kids have actually inherited a little bit of that. And so that dedication and focus that your work needs to be about more than you, it needs to be about more than yourself and how do you give back to the world that you're in, that's shaped each of us today."

Will Reeve reflected on his dad's legacy as "Superman" but also as a super dad and human being.

"Superman to me is my father, Christopher Reeve. But not because he played the role; that's a coincidence. My dad was Superman to me because he was my dad, much like many children think of their dad as Superman because it's dad," Will Reeve said.

"And something that our dad definitely instilled in us was that Superman was a role, it was a job that then took on such a larger-than-life connotation and meaning. But for him, he cared about who he was and who we were as people and that's why he was Superman," he added.

"Super/Man: The Christopher Reeve Story" premiered at the Sundance Film Festival in January. It is set for a limited theatrical release in U.S. theaters Sept. 21 and 25, with tickets available via Fathom Events.