ET's Ash Crossan caught up with the pair on the red carpet of the D23 Expo in Anaheim, California on Friday, where they discussed how, after the cataclysmic events of Avengers: Infinity War and Avengers: Endgame, Vision will somehow return to the fold and how it will affect his romance with the the Scarlet Witch (Olsen).
"Through the genius of [producer and Marvel Studios president] Kevin Feige and the writing team of Marvel," the 48-year-old British actor proclaimed when asked how his character will reemerge from certain death in Infinity War. When asked to elaborate on how this resurrection will take place, he got cagey, offering how work on the new series began.
"When Kevin pitched it to me, we were both blown away by-I would never have thought that this is where they're gonna ask us to go," Bettany said. "This six hours of Wanda and Vision and it's so bizarre and so odd and so moving. And funny. And then eventually it tumbles into some epic, more familiar Marvel action narrative, which is really fun."
Olsen chimed in, hinting at what her powerful character will be exploring in the forthcoming project and a different side of Wanda that might emerge.
"I'm excited for a lot of things," she gushed, later adding, "I've always been lucky to have these beautiful little through lines that end up bringing a lot of heart or plot points, and things and like that to it, because of the nature of Scarlet Witch's powers and her inability to control her emotions and her powers …and I'm excited to play around with this lighter side of her."
"I'm excited to be surprised by what we come up with on the day, I'm just excited for character development that isn't so linear," Olsen added. "And it's back to falling in love with the comics and the character in the comics and just doing the deep dive into what makes her her, that's not just pain and sadness."
First announced at Marvel's panel at San Diego Comic-Con last month, WandaVision will follow the epic events of Endgame and include grown-up Monica Rambeau, played by Akira Akbar in Captain Marvel and now, as a superhero in her own right, by Teyonah Parris.
While on the red carpet, Olsen continued toying with a diamond ring on her left ringer finger, prompting her to explain: "It's like a beautiful cocktail ring."
When asked if it is indeed a cocktail ring, she demurred: "I don't know."
Earlier this month, multiple reports surfaced that the 30-year-old actress is engaged to Milo Greene frontman Robbie Arnett. The pair have been romantically linked since March 2017 and have walked red carpets together since.
Disney's streaming platform launches on Nov. 12. WandaVision is expected to arrive in 2021.
Get all latest updates from D23 by checking out ET's live updates from the festivities.