Bollywood superstar Amitabh Bachchan will be the first Indian celebrity to lend his voice to Amazon's Alexa digital assistant starting next year, as the Silicon Valley giant expands its presence in the massive market. 

The 77-year-old actor has been a household name in India for nearly half a century, and his deep baritone is instantly recognisable to listeners in the country of 1.3 billion.

Foreign firms such as Amazon have spent tens of billions of dollars in India in recent years as they fight for a piece of the Asian giant's burgeoning digital economy. 

In a blog post on Monday, Amazon India said Bachchan's "voice experience" feature will become available for purchase on Alexa next year.

"It will include popular offerings like jokes, weather, shayaris (poetry), motivational quotes, advice and more," the firm said.