With over 7 million views and counting on YouTube alone, the first trailer for “Obi-Wan Kenobi” has gone as viral as expected, considering it marks Ewan McGregor’s return to the “Star Wars” universe nearly 17 years after “Revenge of the Sith.” But McGregor isn’t the only prequel trilogy actor returning for the Disney Plus series. Hayden Christensen is back as Anakin Skywalker/Darth Vader, although the villain was strategically left out of the teaser trailer. How is Vader set to return?  “I wish I could tell you,” Christensen recently told Entertainment Weekly. “I’m sworn to secrecy.”

“Obi-Wan Kenobi” is set in the years between “Revenge of the Sith” and “A New Hope.” McGregor’s Jedi lives in secret on Tatooine watching over a young Luke Skywalker. The Empire is hellbent on removing all Jedi from the galaxy and searches for Obi-Wan. One of the series’ main villains is the Grand Inquisitor, who reports directly to Darth Vader.

“We’re going to see a very powerful Vader,” Christensen added to EW. Fans have been expecting this considering “Obi-Wan Kenobi” is set during a period of time when Vader has risen to new levels of power. If the terrifying Vader that fans saw in “Rogue One” is any indication (the series takes place before that spinoff film), expect Christensen’s Vader to be more ruthless than fans have ever seen him.

“His shadow is cast across so much of what we do,” series writer Joby Harold said. “And the degree of his proximity to that shadow is something that we’ll discover. But he is very much a part of the show emotionally for Obi-Wan, and possibly beyond that as well.”

Concept art for “Obi-Wan Kenobi” already let it slip that McGregor and Christensen will be reunited on screen for a lightsaber battle, but it’s anyone’s guess how the show builds to that point.

“I think it’s no secret that Hayden Christensen comes back and we got to play scenes together again as Obi-Wan Kenobi and Anakin Skywalker and it was just fantastic to work with him again,” McGregor told Forbes earlier this year.

Lucasfilm president Kathleen Kennedy added to Empire, “The thing that was most exciting was being on the set and watching [McGregor and Christensen] get excited. They hadn’t seen one another in a long time. I was surprised at just how incredibly emotional it was for each of them to find themselves back in these roles, and just realizing how important ‘Star Wars’ was to each of them. It was the beginning of their careers.”

“Obi-Wan Kenobi” premieres May 25 on Disney Plus.