Marvel Comics co-creator Stan Lee attends a tribute event "Extraordinary: Stan Lee" at the Saban Theatre in Beverly Hills, California, U.S., August 22, 2017. REUTERS/Mario Anzuoni - RC17A73DF4E0

Stan Lee, 92-year-old comic book legend, signs autographs to fans at the premiere of Marvel's "Ant-Man" in Hollywood, California June 29, 2015.

U.S. President George W. Bush (R) shares a light moment with comic book creator Stan Lee as Lee is presented with a National Medal of Arts during a ceremony at the White House in Washington, November 17, 2008.

Stan Lee gestures as he poses at the premiere of "Iron Man 3" at El Capitan theatre in Hollywood, California April 24, 2013. The movie opens in the U.S. on May 3.

Stan Lee, former president and chairman of Marvel Comics, and wife Joan gesture as they arrive at the 23rd annual Producers Guild Awards in Beverly Hills, California, January 21, 2012. Lee received the Guild's Vanguard Award at the event.

Executive producer Stan Lee signs autographs at the premiere of "Doctor Strange" in Hollywood, California U.S., October 20, 2016.

The World Premiere of “Spider-Man: Homecoming” – Arrivals – Los Angeles, California, U.S., 28/06/2017 - Spider-Man co-creator Stan Lee. REUTERS/Mario Anzuoni

Marvel Comics co-creator Stan Lee shows his hands after placing them in cement during a ceremony in the forecourt of the TCL Chinese theatre in Los Angeles, California, U.S., July 18, 2017.

Image used for illustrative purpose. Comic book creator Stan Lee touches his newly unveiled star on the Hollywood Walk of Fame in Hollywood, California, January 4, 2011. It was the 2,428th star on the Walk of Fame.

Comic book creator and executive producer Stan Lee (L) poses alongside cast member Scarlett Johansson (R) at the world premiere of the film "Marvel's The Avengers" in Hollywood, California April 11, 2012.

Stan Lee (R) creator of comic book character 'The Hulk' and actor Lou Ferrigno, who portrayed 'The Hulk' on television, give their best 'Hulk' pose for photographers at the premiere of the new action film "The Hulk" in Los Angeles June 17, 2003. The film is based on the popular comic book character stars Eric Bana as the Hulk and opens June 20 in the United States. Ferrigno appears in the film.

Premiere of “Avengers: Infinity War” - Arrivals - Los Angeles, California, U.S., 23/04/2018 - Actor Chadwick Boseman (L) and comic book legend Stan Lee. REUTERS/Mario Anzuoni - HP1EE4O089H27

Stan Lee (L) greets cast member Chadwick Boseman at the premiere of "Black Panther" in Los Angeles, California, U.S., January 29, 2018.

Comic book creator and executive producer Stan Lee poses on a motorcycle at the world premiere of the film "Marvel's The Avengers" in Hollywood, California, April 11, 2012.

Marvel Comics co-creator Stan Lee poses with actress Nichelle Nichols after placing his hand, footprints and signature in cement during a ceremony in the forecourt of the TCL Chinese theatre in Los Angeles, California, U.S., July 18, 2017.