depth of field – Canon 70D – shooting video interviews in bright conditions with low aperture

I’m trying to shoot an interview in the middle of the, in the outdoors – which means, it’s very bright.
While keeping the aperture low – to keep the interviewee’s face in focus, with narrow depth of field (2.8f) – and lowering the ISO as much as my Canon 70D allows (100), the image is extremely bright. In fact, the image looks just like a big bright spot, I’m not able to focus on the subject at all.

Which other setting/mode can help me to be able to shoot video interviews with bright daylight, while keeping depth of field?

I’m using a “pancake” lens (Canon EF-S 24mm f/2.8 STM Lens) and in accordance with the “180° law” – keeping the shutter speed to 1/50s because I’m shooting 24fps.