Speaking to Entertainment Tonight at the 'Avengers: Endgame' world premiere in Los Angeles on Monday he said: "I got a script, but it was a dummy. There were scenes in there that I thought we were shooting that nobody ever shot."
Mark went on to insist that he's been "dying" to see the film - which will wrap up phase three of the MCU and see an end to 21 films and 11 franchises taking place over the course of a decade - because he held off seeing previews because he wanted to "experience" the screening in a full cinema.
"I've been dying to see it. We had a chance to see it yesterday, but I held off because I want to see it with an audience, I want to be in that experience with you guys. Yeah, that's when it really means something."
Anthony, 49, insisted that he and his brother Joe feel they're doing the cast a "favour" with the fake scripts by making it easier to keep secrets.
He explained: "It's like doing them a favour, because it's hard to keep secrets, it's hard to keep your mouth closed.
"We spend all day, everyday, doing this for like, the past couple years. So it's hard not to talk about what you spend all your time doing. It's a little bit of a mercy we give them by not giving them too much information."