For the song 'Galliyan', both Sidharth and Shraddha stayed underwater in Mauritius and took just a few breaks.
They took rigorous lessons in Mumbai before taking the plunge, the makers said in a statement here.
The song track will release this week.
In real life, Shraddha is a trained diver and Sidharth is a water enthusiast, who looks forward to becoming a certified scuba diver soon.
Directed by Mohit Suri, 'Ek Villain' also stars Riteish Deshmukh and Kamaal R Khan and is scheduled to release in June this year.