I watched The Mayor of Sunset Strip last night and was surprised by Brian's appearances in the film. Today, I found his performance of "Rodney on the ROQ" on YouTube and was surprised by how well Brian belted out the high parts. I assume that the very beginning of the song includes a non-Brian Rodney jingle (repeated again in the middle of the song) - correct? But, the rest of the song sounded like multi-track Brian in fine form.
Did Brian write the song? When was it recorded?
Not an answer to your question, but as I recall there's a bonus feature on that DVD with Brian in a room with Rodney and maybe Elvis Costello? Can't remember. Anyway, I remember that Brian was so, so natural and relaxed. It was great (and amazing) to see.