An increasing number of lead actors in the Hindi film industry are no longer content to only emote and dance in their films - singing your own songs is the new trend in Bollywood.

Ever on the look out for that elusive success formula which will send box office collections soaring, filmmakers are making this hitherto rare phenomenon now a "must have" in masala films.

Over the last few weeks, actor Vivek Oberoi has sung for "Deewane Huye Paagal", Boman Irani and Sanjay Dutt have sung solos for "Home Delivery", Sanjay Dutt and John Abraham have lent their voice for "Zinda", 83-year-old Dev Anand is doing a rap number in "Mr.Prime Minister" and Aamir Khan is ready to record a song for his forthcoming film "Rang De Basanti".

Even the mighty Shah Rukh Khan had done a pop song for "Josh". In most cases the idea has been to establish the character played by the actor. In fact muscleman Sanjay Dutt has emerged as a very successful 'singing star'.

The trend was actually re-introduced by Aamir Khan who sang his way into the hearts of the movie-going audience with his song "Aati kya khandala..." (Wanna come to Khandala) in "Ghulam".

Actor Sanjay Dutt crooned a song in the film "Khoobsurat" followed by Salman Khan and Govinda. Songs and dance numbers are an integral part of Indian commercial cinema and all mainstream films are musicals.

In the 1930s and 40s actors used to sing their own songs. Film stars like Kundan Lal Sehgal, Suraiya and Noorjehan were singing sensations in their own right. But at that time it was more a case of compulsion as the concept of playback singing and lip-syncing was not prevalent.

Voiceover artistes or playback singers replaced the singing star in the late 1940s, and since then the actors have been content moving their lips to the playback singer's voice.

The only exception was Kishore Kumar who carved out a niche as a singing star.

The only time actors took to the microphone after playback singers became established was when Raj Kapoor sang "O duniya ke rehne wale..." in "Dil Ki Rani" in 1947. Female actors have been less daring with the only exception being Nutan.

If there was one lead star who commanded the maximum attention as a 'singer', it was Amitabh Bachchan. From "Silsila" to "Baghban", every time he has sung in a movie it has led to maximum impact.

While star crazy Indian audiences have given the thumbs up to the phenomenon of singing stars, film critics like Amod Mehra remain cynical.

Mehra says there is nothing even remotely artistic about this new trend as, unlike in the case of singing stars of yesteryears, the present crop of stars are bad singers.

"It's all commercial. Just another gimmick by the film makers to demand a better price for their film from the distributors and exhibitors," he says.

The trend is catching on given the state-of-the-art recording software that is a vital tool for enhancing a raw voice - if needed or preferred.

Singing actors and playback singers are likely to co-exist in the same manner as female actors have to put up with girls doing item numbers in their films.