Beyond that they consider brand fitment, the number of days required, the longevity of the contract, exclusivity, etc.

"In many cases, the celeb may not be against using the brand or may prefer it but may not end up using it exclusively. It is well understood and accepted that some of the downmarket or mass brands may not find a place in the celeb's wardrobe. Do you really expect Govinda to ride a cycle or Sanjay Dutt to wear a particular mass-ish innerwear? It is like creative liberty an adman takes when he creates a hyperbole commercial or when a star is shown fighting 40 people and winning," he says.

Harish Bijoor Consults' eponymous chief talks of four levels at which a campaign works in the consumers' mind. At the first, creating awareness of a product, celebrities really do a good job, scoring 10 on 10.

"However, at the second level of stoking a desire to buy a product, celebrities' strike rate is two out of 10. At the third level of creating the action of sale, celebrities work 0.5 out of 10," says Bijoor.

However, there is some recovery at the fourth level. After the sale, when consumers wonder if they made the right decision, celebrities make them feel that it was right.

Image: Indian footballer and Nike brand ambassador Baichun Bhutia spins a football at the launch of the "Total 90" range of football products in Mumbai | Photograph: Sebastian D'Souza/AFP/Getty Images