The actress, who made her name in South Indian cinema, also said that she has not met with Khan following the movie's end of production.
She told The Times of India: "I can pick up the phone on Salman whenever I wish and he will always be there.
"However, I rarely meet him when we are not shooting together. I haven't seen him after Ready. I am friends with his family.
"I respect his parents and I am in touch with his brothers and sisters. Salman doesn't need to show that we are friends in overtly ways."
Thottumkal also denied that she has lost touch with her roots in South Indian cinema.
"Somewhere I am very attached to my roots. I know that it's the Southern film industries that have made me an actor and that is where people relate to me the most," she said.
"I would never give it up or separate myself from it. I have a personal connection with each of the industries there."
Thottumkal will next be seen in ensemble comedy Housefull 2 and Bol Bachchan following the success of Ready.
Watch the trailer for Ready below: