During an appearance over the weekend at Emerald City Comicon, comic book legend and self-professed "cameo specialist" Stan Lee discussed his lengthy career and also teased a few of his upcoming projects.

One of those is Kevin Smith's "Mallrats 2," the sequel to the 1995 romantic comedy that helped kickstart the Marvel icon's cameo career. During the panel, Lee revealed his role in the sequel will be more than substantial than just a cameo.

Even if he has a more substantial part to play in "Mallrats 2," Lee still has a few more cameos on the horizon. When an audience member asked him to name his favorite cameo, Lee replied, "My favorite is one I can't tell you about, but I'll give you a hint -- don't miss the new 'Avengers' movie!"

Lee also spent time reflecting on his reputation as the king of cameos. "Almost every day, I get invited to do a cameo in some movie or another that has nothing to do with Marvel," he said. "They just call me up, 'Hey, we're doing a movie. Do you want to do a cameo?' It's kind of funny -- I've become known as a cameo specialist."

Some fans have even come up with a theory that unifies Lee's cameos by making them all appearances by Uatu the Watcher. Lee, who created the Watcher with Jack Kirby in 1963, erupted into laughter upon hearing this idea from an audience member. "I haven't heard that," he said, "but it's a good idea!"

Keep your eyes open for Lee's cameo in "Avengers: Age of Ultron," opening in theaters on May 1.