useTheme() not working in Gatsby page or template files

[mr-toast]

Hi I'm using Gatsby, and having issues with useTheme()

It works in a component but not a page or template

COMPONENT
const theme = useTheme()
console.log(theme)
// This returns an object {} with all my theme settings in it.

PAGE or TEMPLATE
const theme = useTheme()
console.log(theme)
// Just returns an empty object {}

I've searched everywhere and can't find out why, does it work differently when not in a component?