Had you been in India in the weeks leading up to the opening of Ra.One, a London-set science-fiction epic billed as Bollywood's most expensive film yet, you could hardly have escaped its lead character. Played by Hindi cinema's golden boy Shah Rukh Khan (known as SRK), he was everywhere: on TV, in newspapers, on billboards, online, emblazoned on India's Formula 1 cars - even under your arm, thanks to Ra.One deodorant.

This was the $26m (€20m) production that would show that kid-friendly special-effects films need no longer be Hollywood's moneymaking licence, a 3D superhero film that would save big-screen entertainment from its small-screen foes. "Local cinema is dying the world over. If we do not evolve we will lose the Indian audience for Indian cinema," SRK told India's The Economic Times.

Given such hype and ambition, this was always going to be Mission: Impossible even for a superstar who, for much of the planet, is bigger than Tom Cruise. Opening on 3,100 screens across India and 904 prints overseas, the film raced to record the highest single-day gross for an Indian film, $4.9m (€3.7m) on 27 October. But since then, mediocre reviews have caught up. The film is currently the fourth highest-grossing Bollywood film worldwide, generating a respectable $20m. Avatar made more money than that in India alone.

Not that the two Mumbai-based production houses behind Ra.One - Eros International, which distributed the film and SRK's own Red Chillies Entertainment, which also did the special effects - are unduly worried. Using a pre-sales strategy common on star-driven Bollywood films, their backs were already covered before the film hit the multiplexes as a result of lucrative satellite, music and product merchandising deals.

"Even before the film opened, we have recovered at least 60%-70% or even more of the cost of the making of the film," says Kamal Jain, chief financial officer of Eros International. "We try to do this with all of our releases and as a standard anything from 40%-80% of our films are funded before they even hit the box office."

Komal Nahta, editor of Indian trade journal Film Information, estimates that Eros stands to make a profit of $5m-$6m, which roughly equates to the subsidy the film received from the UK government in return for shooting car chases around London and a fight scene at Battersea Power Station. In other words, Eros will see a healthy but hardly jaw-dropping investment return of around 20%.

But where Ra.One has broken records is in its promotional blitz, an innovative use of every available media that is reckoned to be India's largest marketing campaign ever at $8m. Some $3m alone was reportedly set aside by Red Chillies for online and social media promotion alone. With no stone or pixel left unturned, Ra.One serves as a case study in digital carpet-bombing that sets the bar for not only Bollywood productions but Hollywood ones too as US studios try to marshal the Facebook generation.