New Delhi, Apr 23 (ANI): Bollywood superstar Salman Khan, who will be seen as a wrestler in his new film 'Sultan', revealed the reason on why he signed a sports based film at the age of 50.Salman Khan will be announced as the Goodwill Ambassador for the Indian contingent at Rio Olympics, this year. This is the first time that a Bollywood superstar will be a goodwill ambassador for the national squad for as big as an event like the Summer Olympics.