Voiceover Master Don LaFontaine has died. He was 68.

LaFontaine, far right, is pictured above with ET's Mark Steines and Mary Hart, and fellow voiceover artist Randy Thomas.

LaFontaine, known as the "King of Voiceovers," died Monday afternoon at Cedars-Sinai Medical Center in Los Angeles. LaFontaine's agent, Vanessa Gilbert, tells ET that he passed away following complications from Pneumothorax, the presence of air or gas in the pleural cavity, the result of a collapsed lung. The official cause of death has not yet been released.

Over the past 25 years, LaFontaine cemented his position as the "King of Voiceovers." Aside from being the preeminent voice in the movie trailer industry, Don also worked as the voice of Entertainment Tonight and The Insider, as well as for CBS, NBC, ABC, Fox and UPN, in addition to TNT, TBS and the Cartoon Network. By conservative estimates, he voiced hundreds of thousands of television and radio spots, including commercials for Chevrolet, Pontiac, Ford, Budweiser, McDonalds, Coke, and many other corporate sponsors.

He recently parodied himself on a series of national television commercials for Geico. At last count, he has worked on nearly 5000 films, including appearances as the in-show announcer for the Screen Actors Guild and Academy Awards. Based on contracts signed, he has the distinction of being perhaps the single busiest actor in the history of SAG. Don is survived by his wife -- singer/actress Nita Whitaker, and three children: Christine, Skye and Elyse.