Colman will step into the role of Elizabeth II for the series' third and fourth seasons as the action of the show moves closer toward the present day.
Foy, who will be seen playing the role of Queen Elizabeth in the upcoming second season of the series, has revealed that she is "thrilled" to pass the crown to Colman.
While talking to Vanity Fair, at this year's B.A.F.T.A. Britannia Awards, Foy said, "I've known for a long time. I found out many, many months ago, and I was just like, yes, just do it! Whatever happens, don't let her get away. Make her do it."
Adding, "It was to the point where I actually spoke to her on the phone and told her, you have to do it. You have to do it! She's the most extraordinary actress and person in every single way. I love her, so I'm thrilled. I have always loved her. I can't wait to see her in it."
Asked if she had any advice for Colman, she replied, "There's no shortcut in playing the Queen. It's for her to discover, and she'll probably find out lots of things that I never found out. She'll play the Queen at a very different time to me. It's a rolling thing, and it's ever-changing and ever-revolving. I think the most important thing for her is to just do it, and not think about anyone else who has ever done it before. It's a challenging role, but she knows what she's doing. She'll completely reinvent it and make it her own."