New Delhi: Actor Sidharth Malhotra has only words of praise for his "Baar Baar Dekho" co-star Katrina Kaif. He says the actress is very serious about her work. "Katrina takes her work very seriously and is very passionate when it comes to her characters," Sidharth told IANS. The 31-year-old star says she also works really hard in the gym to look her best. "We used to often bump into each other at the gym. It was great to have another fitness freak around," he said of his experience of working with he in "Baar Baar Dekho". Katrina is even always up for rehearsals and improvisations, shared the "Ek Villain" star, who added: "It has been fabulous to have her as my co-star".