Marvel legend Stan Lee has a cameo at the end but otherwise, 'The Avengers' is very light on Easter eggs.  Except when it comes to a very well-disguised cameo from a former Hulk...

As it turns out, when it came to creating the Hulk's roar for 'The Avengers' sound designer Christopher Boyes went back to an old friend to help get just the right sound.

IGN has posted a new video interview from Sound Works Collection with Boyes, who served as Sound Designer, Supervising Sound Editor and Re-recording Mixer on the film. At around the 3:15 mark, he begins to explain how he arrived at the sound of the new Hulk. His mandate from director Joss Whedon was to make the Green Goliath sound less monster-like and more "superhuman" or even "human in rage."

Boyes relates how he came up with about 15 different samples, of which Whedon picked the one he liked best. And that one, Boyes reveals, was a mix of his own voice, that of Mark Ruffalo (who plays Dr. Bruce Banner), two New Zealand actors...and Lou Ferrigno.

Yes, the first (and so far, only) actual human actor to get painted green and play the Hulk in the classic late '70s TV series -- who also, by the way, lent his voice to the character for 2008's 'The Incredible Hulk' film -- has contributed to the iconic role again, in perhaps his best incarnation yet.

You can watch the talk with Boyes below. We think it's only fitting that Ferrigno is still making a contribution to the Hulk and the Marvel Universe, don't you?