"G.One stands for the good one & sustainer of life. To protect life he is ready to put his own [on] the line. Hope u all like him....will show soon," Khan tweeted on May 31.
The 44-year-old actor, who has had to loose a lot of weight for his super-hero role, joked that he feels G.One could well stand for Gaunt One.
"After losing so much weight i feel g stands for the gaunt one," he tweeted.
The name of the film - Ra.One - is short for Random Access Version 1. The film targets kids and is about a superhero who can freeze electricity.
Khan plays a Miami based software engineer named Shekhar, who as a video-game hero takes on his self-created techno-monster Ra One.
The film, set in London, additionally stars Kareena Kapoor and Sahana Goswami.
Kareena plays lead in the film, opposite Khan, as a young mother of an eight-year old. When he falls in love with Kareena, Khan imagines her as one of the characters.
Sahana's character in the film helps out Shah Rukh's when a gaming character causes problems for him.
"Ra.One is a very ambitious project. It's a film that kids will enjoy for sure. It's not only for kids but the idea is also to bring action to a different level. It's hugely experimental," says Arjun Rampal who plays villain in the film.
American singer Akon recorded a song for the film in Mumbai.
Filming started in India on March 24 and is close to wrapping up. Next, a schedule is planned in London, starting in the first week of July.
The film will have state-of-the-art special effects provided by Hollywood technicians.