The news was announced during the weekend by Openfilm, the Miami online technology company of which Caan is chairman.
His character, described as "a suave and debonair chili pepper," debuted in a short film Saturday.
Created by Dane Boedigheimer for Gag Films, "The Annoying Orange" is a Web series sensation starring a smart-talking piece of fruit and his various produce targets. Since it debuted in October 2009, the series has accumulated more than 200 million views, making it one of the Top 10 most subscribed channels on YouTube, Openfilm said.
Caan's appearance is the series' first by a famous Hollywood actor.
"It's amazing what the Internet can do for independent artists," Caan said in a statement Saturday. "The studio movies of today are mostly grand productions. For those people who want to make smaller, more character-driven stories for the big screen, the Internet offers incredible opportunities for them to gain initial exposure and momentum for their films."
Caan's film credits include "Brian's Song," "The Godfather," "Alien Nation" and "Misery."