Hello!
Yes, absolutely - speaking about fine art or ballet is completely acceptable (and likely an interesting read for the grad rec team!). The question is designed to see you as a person, not to test your commercial awareness or squeeze in more motivation towards law. As long as you explain why you're passionate about it and what it says about you (e.g. discipline, creativity, attention to detail, long-term commitment, etc), it can leave a strong and memorable impression. I often used to talk about my interest in motorsport in these types of questions, so I'd pick something you are genuinely passionate about!
A lot of firms (such as
Bristows) tend to value individuality and depth of interest, so writing about something non-law-related can definitely help you stand out! What matters most is that you reflect thoughtfully on the experience and show self-awareness, rather than trying to force it into a legal lens.
Hope that helps, and best of luck with the
Bristows application!