I think I might know who you mean, Milly. Even though I haven't watched that part of the concert back on my recording, there is a Prommer who looks quite like George...
Alternatively it could have been a little grey wolf from Grimaud's wolf sanctuary...
(By the way, off topic: yes, A, I did enjoy Don Giovanni. I've seen the production before, and it has its weird moments, but is generally serviceable and I do enjoy the last two scenes. I thought the men were excellent, as was Joyce DiDonato, but got really irritated with Poplavskaya's swooping portamenti, haphazard intonation and non-existent diction. I also wasn't too keen on Persson's rather strident and monochrome Zerlina at first, but she was far better in Act 2. There were a few ensemble problems, and an excess of vocal ornamentation in the arias. We got Robert Murray in place of Ramon Vargas, which I didn't mind at all, given that a few people who saw it last week have mentioned that they didn't much rate his performance.)