With Sylvester Stallone's magnum opus "The Expendables" coming to theaters next week, audiences will once again be reunited with the Stallone we know and love best: a take-no-prisoners, gun-wielding, no-nonsense badass with arms the size of boa constrictors.

But underneath his gritty exterior lies the soul of a jovial individual with an appreciation for wholesome and witty show tunes.

America became acquainted with this side of Stallone in his 1979 appearance on Jim Henson's "The Muppet Show," where he sang a unique rendition of "Let's Call the Whole Thing Off" with an anthropomorphic lion.

He could have at least done a solid for Kermit by giving him a cameo in "Rocky III."

See the video after the jump.