The film will be directed by Bill Condon, who most recently helmed Disney's "Beauty and the Beast", reported Deadline.
Condon will also produce with Greg Yolen.
Jeffrey Hatcher has written the screenplay for "The Good Liar", based on the novel by Nicholas Searle.
New Line acquired rights to the book two years ago.
The film revolves around career con artist Roy Courtnay (McKellen), who can hardly believe his luck when he meets well-to-do widow Betty McLeish (Mirren) online. As Betty opens her home and life to him, Roy is surprised to find himself caring about her, turning what should be a cut-and-dry swindle into the most treacherous tightrope walk of his life.