Well, this is going to get everyone talking. Sting appeared in the first part of the Ultimate Warrior Week special that aired tonight, talking about his memories of the Ultimate Warrior. In the interview, he talks about training with Warrior and said that the late Hall of Famer used to put tuna fish and orange juice in a blender and tell him that he was getting his Warrior dose of protein & Vitamin C.
This is Sting's first-ever appearance for WWE in any capacity. As you likely know if you've been paying attention to news, there has been a ton of speculation about Sting's potential WWE signing, with recent reports saying he had a contract offer but had not signed it yet. This could indicate that he has signed, or it could conceivably be a one-off appearance in honor of his early tag team partner.
We reported over the weekend that Sting hadn't signed his WWE contract but is expected to at any point. As noted, the deal is done "in principle" and has been for a while; it is now just a matter of pen hitting paper.
Also and to few people's surprise, that the belief is he will not be wrestling on a regular basis.