"Captain America: Civil War" is packed with major reveals -- including what young Tony Stark looked like. Of course the character looked a lot like young Robert Downey Jr. -- literally. "Civil War's" visual effects team used cutting edge techniques to de-age RDJ, which was a feat made easier by the fact that the actor's been in show business since he was 18 years old. In an interview with The Wrap "Civil War" effects supervisor Dan DeLeeuw revealed how the scene came to be, and which '80s films they looked to for inspiration.

The 4,000-frame sequence concludes with adult Tony sharing the screen with his younger self. That was accomplished by Downey performing the scene twice with stand-ins filling in for the other Stark each time. He played the older Tony first, and then shaved and returned to perform the younger Stark, mimicking the movements of the stand-in.

To create the younger Tony the visual effects artists looked at Downey's performances in three movies: 1985's "Weird Science," 1986's "Back to School" and 1987's "Less Than Zero."

"We went a little closer to [his look in] 'Less Than Zero,'" said visual effects supervisor Dan DeLeeuw. "No one wanted the spikey hair from 'Weird Science' like I did!"

DeLeeuw added that it took multiple passes to get Downey down to the desired age. "Each pass is sculpting in a way," said DeLeeuw. "Pulling off material, pulling off age ... When it feels right, you go back and clean it up."

You can see the young Tony Stark in "Captain America: Civil War," which is in theaters now.