The all-star Marvel epic is out next month, and a new trailer dropped late last week.
With such a huge cast on board, it’s no surprise that the action doesn’t let up for one moment.
Speaking to Entertainment Weekly, Cumberbatch said: “It’s just mind-blowingly epic.
“What I thought is, ‘this just doesn’t stop’. Once it starts, it does. Not. Stop.”
He added: “It’s just this horrible, brilliant, terrifying, at times funny, at times very moving, relentless action.
“It’s like everyone’s constantly in crisis, and catching up with themselves, and it’s really breathless to read a script like that.
“This isn’t a slow burn. You’re really thrown in helter-skelter. It’s got a lot of facets to it, but I think the main one for me was just how utterly relentless the events and action were.”
Cumberbatch is back as Doctor Strange in the film, and was seen in Friday’s trailer having a brief humorous exchange with Tom Holland (Spider-Man).
He was also seen to be in huge danger at one point – one of many characters whose lives were seemingly on the line.
It’s no secret that several MCU favourites will be exiting the franchise in either Infinity War or its as-yet-untitled follow-up – but could Doctor Strange be one of them?
Avengers: Infinity War is out on April 26.