No! That's not true! That's impossible!
Making Star Wars has heard through the Jedi grapevine that Hayden Christensen, who portrayed young Anakin Skywalker in the prequels, is making an appearance in Rian Johnson's Star Wars: Episode VIII. They report: "A team in the U.K. are soon heading to the U.S. to begin training Hayden Christensen for a Star Wars: Episode VIII appearance of some sort."
Training?! That doesn't sound like a mere appearance from a ghost of Anakin. So that leaves us with two possibilities: Anakin flashback scene(s) or he is resurrected -- from the dead or as a clone -- by Kylo Ren, who is obsessed with Darth Vader.
There is a popular fan theory that is currently circulating that seems very relevent to this latest rumor. Click here to check it out.
Making Star Wars also has some additional info regarding Darth Vader appearing Star Wars: Rogue One. "The most I have heard at this juncture is that a fully operational Darth Vader chest piece along with the helmet made it to the creature shop for the next film," they report. "The lights on the chest piece work and everything." However, only one was spotted, indicating Darth Vader's screentime would be very limited -- no action scenes of any sort. Though, this chest piece might just be used a reference for the prop shop to churn out multiple pieces. However, filming has already begun and you would figure multiple suits would've been dealt with in pre-production.