Can you add more than one iMovie Theater account to an Apple TV? I have a 3rd generation Apple TV and typically have the iCloud account set to mine. However, another member of my family is starting to use iMovie Theater and their videos do not appear on the Apple TV as we have separate iCloud accounts. It seems that the iMovie Theater app on the TV is tied to a single iCloud account.

I know that you can add multiple iTunes accounts to the device, but is it possible to add multiple iCloud accounts? Ultimately, I'm looking to have the iMovie Theater show videos from both of our accounts.
As of June 2019, iMovie Theater is no longer supported and people are being moved to using iCloud Photos instead.

That being said, it appears that there is no way to add an additional account to the 3rd generation Apple TV, only the one iCloud account is allowed and thus only one iMovie Theater account can be used at a time. If you want to switch, you need to log out/in with the other account.