There is another issue in that, with a PhD in film, HR at firms will likely question your commitment to the cause. I've heard even doing a PhD in Law will cast doubt on their part.
However, MagicNMedicine seems to be assuming you want to go into law, which is not necessarily the case. An LLB is valued by employers across a wide range of sectors. But you would need some additional CV stuff involving doing internships/work experience in a relevant area to make yourself a viable candidate. The legal profession is a very competitive one, and you would be wise to consider different sectors. My two cents: an LLB will help, but make sure you get work experience during it.