A couple of years ago Robert Downey Jr's career was dead. He and Val Kilmer starred together in the incredible Kiss Kiss Bang Bang and nobody came to see it. Now things have changed; Downey is a major star (Kilmer, not so much). He's parlayed his fame into a voice over gig - he's the voice of Mr. Peanut, Planter's Peanut's longtime mascot. It's the first time Mr. Peanut has had a voice, so I guess it's prestigious.
But more interesting is that it sounds like the other main voice in this commercial is none other than Val Kilmer, playing Richard the Nutcracker. That would make this a Kiss Kiss Bang Bang reunion, which is sort of very exciting! Is it Kilmer's voice? You tell me.