Several Internet sites have an ongoing debate on the issue.
Says Shah Rukh: "I don't see a national debate on the issue. But, yes, a moustache is what my character in 'Paheli' required. My director Amol Palekar thought it suited the character, and that's it. As for whether my fans will like me with a moustache or not... I think they love me no matter what I do. In any case this isn't the first occasion where I sport a moustache."
Shah Rukh has a point.
Some years ago in stunt director Ram Shetty's directorial venture "Army" (a gender-reversed version of "Sholay") Shah Rukh pasted on a moustache to look well matched with his co-star Sridevi.
On the other hand Anil Kapoor, one of the few moustached successful heroes in Bollywood, shaved off his trademark hair-lip to look younger than Sridevi in "Lamhe".
Neither "Army" nor "Lamhe" worked at the box office. Could the moustache have something to do with it?
Whenever our heroes have used a moustachioed look to add character to their role they have erred.
At the peak of his career Amitabh Bachchan tried the route in Desh Mukherjee's "Imaan Dharam".
The film had everything going for it. Besides the awesome Bachchan (paired, oddly enough, with Helen!) it had Salim-Javed's foolproof script, and two of Bachchan's favourite co-stars Shashi Kapoor and Rekha.
"Imaan Dharam" was one of the biggest bombs in the history of Indian cinema. Then again Sudhendu Roy's "Saudagar", regarded by many as one of Bachchan's most accomplished performances, was a box office dud.
Could the moustache have played the villain?
Even Rishi Kapoor, riding the waves of hysteria after debut, erred with the moustache in his post-Bobby film "Zehreela Insaan". It was a box office disaster.
On the other hand, Rajesh Khanna was a smash hit with a moustache in "Dushman" and "Daag", though it did not help his "Shehzaada" or "Mehbooba" much.
Alas, Shah Rukh could not revive the era of the moustache in "Paheli".
Aamir Khan's much talked about hairy look as Mangal Pandey could be a cause for box office concern. The only time Aamir has attempted a growth on his upper lip was in a disastrous film called "Aatank Hi Aatank", a poor remake of "The Godfather" with Aamir trying desperately to look like a dreaded don.
He regards it as the worst performance of his career, though he doesn't blame the moustache for it.
Is the moustache in vogue this year?
Anant Mahadevan is planning to give his leading man Sammir Dattani a mouche to play one of the two characters in the comedy "Do Dooni Chaar".
"It certainly helps give a reflective, sober image to the hero," says Mahadevan. "Since Sammir has a double role, the moustache will help give a distinct identity.
"Remember what a moustache did to Jeetendra in Gulzar's films 'Khushboo', 'Parichay' and 'Kinara'?"
If Aamir Khan's new look works, it could mean a new beginning for the moustache!