"Ranbir is the best star actor this country has seen. He is incredibly effortless and versatile as an actor. While working with him, I realised he uses a method and has a strong process, but never exhibits it," Sayani said in a statement.
"His mind works like a director, so his overall understanding of the mise-en-scene is from a filmmaker's point of view and not just an actor's," she added.
The actress also feels that they share a "similar approach", but says that she is not even "close to his potential as an actor".
"He is such a breeze to work with and even to watch on screen! He is aware, easy, crafted and unassuming," she said.
Sayani, who made her debut in Bollywood with the film 'Margarita With A Straw', also said that Ranbir's "special" quality is that he "never behaves like a star".
She will soon be seen in superstar Shah Rukh Khan starrer 'Fan' and is also busy shooting for 'Baar Baar Dekho'.