Johar, whose production "Kapoor and Sons" has Fawad as one of the protagonists besides Alia Bhatt and Sidharth Malhotra, tweeted about the 33-year-old actor's involvement with "Ae Dil Hai Mushkil".
"Fawad Khan joins the cast of #AeDilHaiMushkil...An extremely "special" role in our film!! Amazing energy on set!" posted Johar.
The filmmaker also shared a photograph of Ranbir, 33, and Fawad from the movie's set.
The cast and crew of the film is currently in Vienna. "Ae Dil Hai Mushkil" dwells on relationships. Johar's last directorial project was "Student of the Year" in 2012.