Hrithik Roshan and his sister Sunaina share a special brother-sister bond and the Hindi film star says a simple smile on his sibling's face is all he needs.

"Let me start by saying what is the best thing she does for me. Every time she smiles, it just adds that little spark I always need in my eyes," Hrithik said in an interview.

The actor is currently busy promoting "Krrish 3", his new superhero thriller slated for a Nov 4 release.

Sunaina enjoys the small little things that her brother does for her.

"He just keeps doing these small things everyday, which means a lot to me because small things later on become big things... it could be a hug, a smile on his face, and it could be seeing him happy," she said.

Sunaina was diagnosed with cervical cancer almost five years back, which she fought and overcame.