Working in Other EU countries?

[canadianactor]

Hi folks,
I have a question that seems a little tricky to answer based on what I've found on here.

I'm Canadian, living in London under the UK Ancestry Visa. I'm registered as self-employed as an actor. I've recently been to a casting for a film that would be filming in Germany in March, and my question is whether or not I can work on this film?

I read that I can leave the country for "business trips", which is what I'm assuming this would be. Obviously I don't want to lie to border control and just say I was going to Germany for a holiday. But if I'm only going for about a week, and being paid in British pounds and paying taxes and NI, is that still fine even though the actual "work" would be done on German soil?

Any help would be great! Thank you.