Larian Studios Forums Divinity - Original Sin Divinity - Original Sin - General Check your Accounts if you purchased the CE.

Larian customer support told me that they had provided Steam early access keys to some of the retailers selling a physical CE and to check with the store I was buying it from if they had any.

I bought mine online and am waiting to see if the store I got it from (Ozgameshop) have any keys.