While there have been rumors that The Rock would be appearing on the show, no formal announcement regarding his involvement has been made.
Footage of The Rock will be a big part of next week's show, since The Rock was a major player during the highest rated years. The Rock was actually a part of the highest rated segment in the history of Monday Night RAW - the infamous "This Is Your Life" skit with Mick Foley. That segment, which aired on September 27th, 1999 drew an absolutely monsterous 8.4 quarter hour rating.
Here's the ad featuring The Rock that WWE is running:
