MUMBAI, April 5, 2009 (AFP) - Indian police have registered a case accusing Bollywood actor Akshay Kumar and his wife of obscenity after she unbuttoned his jeans during a fashion show.

Akshay Kumar (Photo by: AFP/Sajjad Hussain)

Mumbai police said they acted after a complaint was lodged against Kumar and Twinkle Khanna by a social campaigner who called the performance "vulgar and indecent."

Kumar, a brand ambassador for Levi's "Unbuttoned" range, was strutting down the catwalk last week when he stopped in front of his wife, who was seated in the audience, and asked her to undo his trousers.

"We have registered a case against Akshay, Twinkle and the organisers of Lakme Fashion Week," an unnamed police officer told the Press Trust of India news agency late Saturday.

India's obscenity laws are punishable by a maximum of two years' imprisonment and a fine of 2,000 rupees (39 dollars).

The actor has apologised for the incident.

Celebrities have previously landed in hot water over behaviour deemed to be offensive in culturally conservative India.

In 2007 a court issued arrest warrants for actress Shilpa Shetty and Hollywood star Richard Gere after he hugged and kissed her at an AIDS awareness event, but the case was eventually thrown out.