Mallika Sherawat required swimming for a sequence in 'Pyaar Ke Side Effects'. Director Saket Choudhary was so surprised to know that she doesn't know swimming. "How do I know that someone whom we have seen so many times in a swimsuit and on beach doesn't know how to swim? It was very hilarious. She came to me quietly and said she wanted to discuss something quietly. When she told me I couldn't stop laughing and I got a whack on my head," laughs he.