What is brand endorsement by a celebrity?
Brand endorsement is also a sort of focused advertisement strategy wherein a well known icon celebrity lends his or her name and fame to vouch for and promote a particular brand or product. For this the manufacturer enters into a contract with a price and period and with certain expressed and implied conditions.
For example when a cricketer or tennis player says in an audio visual advertisement that so and so drink or food 'is secret of my strength" or " my stamina comes from...(product).." then the celebrity endorses that product. That is called brand endorsement.
How endorsing a brand is different from advertising a product/brand?
An advertisement can be simply textual or pictorial. There will be a model simply giving a pose or holding the product for visibility. In an advertisement for a shirt, we may see the photo of a handsome male, or a professional model or even a celebrity wearing that shirt. There will be prominent words and phrases highlighting brand name and qualities. There will not be any personal message or signature of the model or celebrity. However in endorsements it makes a feeling and appearing to the viewers that the celebrity is using the product or brand and the words an actions are testimonials for inducing others.
Can a celebrity endorse the same type of product e.g soap or hair oil manufactured by two different companies?
Generally the ethics and code of conduct terms prevent that. They are not to endorse the product of the competitors during the contract period or even a cooling period after termination or expiry of that period, if the contract terms specify so.