Mersal (English: Astonish) is a 2017 Indian Tamil-language film starring actor Vijay in triple roles Nithya Menon, Samantha and Kajal Aggarwal playing the female-lead roles. The film is directed by Atlee and co-written by K. V. Vijayendra Prasad, S. Ramana Girivasan and Atlee with background score and soundtrack composed by A. R. Rahman while the cinematography is done by G. K. Vishnu and editing is by Ruben. The Telugu dubbed version is titled as Adhirindhi (English: Excellent).
The film began its production in February 2017 with actors Sathyaraj, S. J. Surya and Vadivelu amongst others in supporting roles. Vijay along with A.R. Rahman are marking their 25th year in the film industry as film actor and music composer, respectively. Thenandal Studios Limited produces their 100th film as Mersal.