Endorsing a brand by a Bollywood celebrity is not a current trend but being done before the independence of the country. The biggest advertiser in India was Lux Soap. The launch of the first Lux soap in India dates back to the year 1929, a black and white Ad that featured a popular actress of the time, Leela Chitnis in 1941. Since then all the popular heroines of their time appeared in Lux advertisements.
On researching on this subject I noticed that most of the Top heroes did appear on one Ad or another except Dev Anand. I came across an Ad of a Pickle company being endorsed by Dilip Kumar, similarly in one Ad of an airline company Raj Kapoor, Balraj Sahni, and Nirupa Roy appeared together.
Lux entered India in 1929 and while its early advertisements would feature Hollywood actresses, Some of these were printed in English newspapers and magazines. Of course, the westernized and elite movie-going Indian audience reading these newspapers would have been able to identify known faces. These two images, for instance, featured in the Times of India Annual of 1937. While their faces may appear vaguely familiar, they do not seem to belong to any recognizable star. Perhaps some of them were just generic images of "glamorous women," the presumed visual iconography of stars.
Appearing in a Lux advertisement was indeed a “must do” thing for a female movie star in India, a way of announcing her arrival in the industry. I am not certain about the first heroine of Bollywood was Leela Chitnis or Devika Rani but either of two may be the first Bollywood celebrities to appear in an Ad. The first Lux Ad with Bollywood Heroine came in the year 1941. I came across of Devika Rani's Ad for Afghan Snow Cream, once very popular in India.