Robert Downey Jr., visits 'Late Show With David Letterman' out and about for CELEBRITY CANDIDS - WEDNESDAY, , New York, NY April 28, 2010. Photo By: Ray Tamarra/Everett Collection - Stock Photo & Image

Robert Downey Jr., visits 'Late Show With David Letterman' out and about for CELEBRITY CANDIDS - WEDNESDAY, , New York, NY April 28, 2010. Photo By: Ray Tamarra/Everett Collection

Robert Downey Jr. at arrivals for IRON MAN 2 Premiere, El Capitan Theatre, Los Angeles, CA April 26, 2010. Photo By: Michael Germana/Everett Collection

Robert Downey Jr. at arrivals for IRON MAN 2 Premiere, El Capitan Theatre, Los Angeles, CA April 26, 2010. Photo By: Dee Cercone/Everett Collection

Robert Downey Jr., visits 'Late Show With David Letterman' out and about for CELEBRITY CANDIDS - WEDNESDAY, , New York, NY April 28, 2010. Photo By: Ray Tamarra/Everett Collection

Robert Downey Jr. at arrivals for IRON MAN Premiere, Grauman''s Chinese Theatre, Los Angeles, CA, April 30, 2008. Photo by: Michael Germana/Everett Collection

Robert Downey Jr. at arrivals for SHERLOCK HOLMES Premiere, Alice Tully Hall at Lincoln Center, New York, NY December 17, 2009. Photo By: Desiree Navarro/Everett Collection

Robert Downey Jr. at arrivals for 2009 Los Angeles Film Festival Opening Night World Premiere of PAPER MAN, Mann''s Village Theatre in Westwood, Los Angeles, CA June 18, 2009. Photo By: Dee Cercone/Everett Collection

Robert Downey Jr. at arrivals for SHERLOCK HOLMES Premiere, Alice Tully Hall at Lincoln Center, New York, NY December 17, 2009. Photo By: Desiree Navarro/Everett Collection

Robert Downey Jr. at arrivals for VANITY FAIR Oscar Party, Sunset Tower Hotel, Los Angeles, CA March 7, 2010. Photo By: Dee Cercone/Everett Collection

Robert Downey Jr. in the press room for The 67th Annual Golden Globes Awards - PRESS ROOM, Beverly Hilton Hotel, Beverly Hills, CA January 17, 2010. Photo By: Dee Cercone/Everett Collection

Robert Downey Jr. at arrivals for 26th Annual Palm Springs International Film Festival Awards Gala 2015 - Part 2, Palm Springs Convention Center, Palm Springs, CA January 3, 2015. Photo By: Xavier Collin/Everett Collection

Robert Downey Jr at arrivals for SHERLOCK HOLMES Premiere, Alice Tully Hall at Lincoln Center, New York, NY December 17, 2009. Photo By: Gregorio T. Binuya/Everett Collection

Robert Downey Jr. at arrivals for THE AVENGERS: AGE OF ULTRON Premiere, The Dolby Theatre at Hollywood and Highland Center, Los Angeles, CA April 13, 2015. Photo By: Elizabeth Goodenough/Everett Collection

Robert Downey Jr. at arrivals for Los Angeles Premiere of TROPIC THUNDER, Mann's Village Theatre in Westwood, Los Angeles, CA, August 11, 2008. Photo by: Dee Cercone/Everett Collection

Robert Downey Jr. at arrivals for 2014 BAFTA Los Angeles Jaguar Britannia Awards Presented by BBC America and United Airlines, The Beverly Hilton Hotel, Beverly Hills, CA October 30, 2014. Photo By: Xavier Collin/Everett Collection

Robert Downey Jr. at arrivals for A SCANNER DARKLY Screening by The Film Society of Lincoln Ce, The Walter Reade Theater, New York, NY, July 05, 2006. Photo by: George Taylor/Everett Collection

Robert Downey Jr at arrivals for SHERLOCK HOLMES Premiere, Alice Tully Hall at Lincoln Center, New York, NY December 17, 2009. Photo By: Gregorio T. Binuya/Everett Collection

Johnny Depp at arrivals for RED CARPET - 80th Annual Academy Awards Oscars Ceremony, The Kodak Theatre, Los Angeles, CA, February 24, 2008. Photo by: David Longendyke/Everett Collection

Robert Downey Jr. at arrivals for Kiss Kiss Bang Bang Premiere, Grauman''s Chinese Theatre, Los Angeles, CA, October 18, 2005. Photo by: David Longendyke/Everett Collection

Robert Downey Jr. at arrivals for A SCANNER DARKLY Screening by The Film Society of Lincoln Center, The Walter Reade Theater, New York, NY, July 05, 2006. Photo by: Brad Barket/Everett Collection

Robert Downey Jr at arrivals for SHERLOCK HOLMES Premiere, Alice Tully Hall at Lincoln Center, New York, NY December 17, 2009. Photo By: Kristin Callahan/Everett Collection