"I emailed Elizabeth and I'm like, 'If you need me for anything in Charlie's Angels, I'm here for you,' " Cox tells Variety. "She (replied), 'Your ears must be burning 'cause we were just talking about you for something.' "
But Cox's hopes were dashed when she learned filming had been completed.
"I run into (Banks) in December of last year, and she's like, 'We just wrapped and it was so intense,' and I was like, 'Oh great... like where was my call?' " Cox adds. "I was like, 'It's not for me, it's fine.' "
That all turned around when Cox received a surprise message from Banks.
"Six months later I get an email, (saying), 'Are you in town next week? Can you come and shoot, like, a little cameo?' And I said, 'I'm in town, let's do it,' " she shared.
Cox ended up appearing as a "bomb instructor" in the project.
"It just means so much to me. Dreams do come true," Cox beams. "I always think about the kid, maybe like nine years old, watching Charlie's Angels in Alabama in, like, the late '70s... The hair flip in the opening sequence - I wanted to be Jaclyn Smith and I was obsessed. And then the Lucy Liu and Cameron Diaz and Drew Barrymore movies came out and I was obsessed. And now I get to be in it."