Imported Image Sequence is Transparent

So I’ve been working on a Star Wars themed project recently and I filmed it against a green screen today. I keyed out everything and exported it as an image sequence.

However, when I bring it into my scene as a plane, light behind it shows through.

I assume this has something to do with the alpha channel of the image, but I don’t know enough about this to know how to fix it. I’d like the background to still be transparent while making the actor opaque.

Here is the node set up it came with when I imported it. https://i.imgur.com/qOG72Xu.png

Any help would be appreciated, thank you!