Just a tiny bit of speculation: both Christoph Waltz and Ralph Fiennes were at the Golden Globes last night. Interesting to think that they both are on a private jet back to the set (not Austria necessarily, of course).
Waltz was having a full head of hair.
Waltz stated in an interview in December that his first day of shooting will be in February or March.
So his look from the Globes hints at nothing, because he isn't working on SPECTRE for at least another month.
Yes, he's also said more recently that he starts in February.
He is involved in the Rome shoot and they start filming there on 19th February. He may start before that if they have studio stuff scheduled for earlier.