Bryan Cranston, cyst signer. (Ursula Coyote/AMC)

With the fifth season premiere of “Breaking Bad” just days away, Bryan Cranston has some publicity responsibilities to uphold. Wednesday night, he upheld them with an appearance on “Late Show With David Letterman,” during which he snacked on pieces of that delightful blue-sky meth he cooks up on “Breaking Bad” — turns out it’s just aquamarine-colored rock candy — and showed Letterman a unique and, uh, post-surgical autograph.

Yes, as the headline above indicates, Cranston once signed his name on a photograph of a cyst that had recently been removed from a fan’s “lady parts,” as Cranston put it. The comic timing on the reveal really would have been spot-on if Letterman hadn’t dozed off with his eyes open in the middle of Cranston’s story.

Watch the tumor-ific clip below.