Star Wars: The Force Awakens had a surprise cameo when the voice of Obi-Wan Kenobi spoke to Rey the first time she had a vision in the Force. You could say it's when the Force awakened in her, and it's a momentous occasion.
The line is delivered, thanks to some movie magic, partially by Sir Alec Guinness and partially by Ewan McGregor, both of whom played the character of Obi-Wan in their own respective trilogies. Now, a rumor says the latter may reprise his role, playing Obi-Wan's Force ghost in the sequel, currently going simply by Star Wars: Episode VIII.
The rumor is unsourced, but being reported by Kristian Harloff of Schmoes Know and Collider, who simply tweeted, "Grain of salt: hearing that Ewan Mcgregor in talks to play Obi Force ghost in Episode 8."
It would make a certain amount of sense, having Obi-Wan play a role, whether he's guiding Rey directly after telling her about her "first steps" last film, or simply maintaining a relationship with his student Luke Skywalker. When Obi-Wan's master, Qui-Gon Jinn died, he became one with the Force, and Obi-Wan had regular talks with him, still receiving training from the Jedi master. Perhaps he'll simply be changing roles, now being the one Luke has been trying to learn from while sitting at the first Jedi temple on Ach-to.