Activist investor Carl Icahn says it's time for Apple to get into the business of making TVs.

In an open letter today to Apple chief executive Tim Cook that focused on the need for more share repurchases, Mr Icahn also said there's "good reason to expect" Apple to introduce an UltraHD television in the 2016 fiscal year.

Mr Icahn said Apple would be able to sell 12 million of the 55-inch and 65-inch TV sets that year and another 25 million in the company’s 2017 fiscal year.

Each TV set would only cost an average of $1,500, Mr Icahn projected.

“Televisions are a centrepiece to the modern living room and thereby a promising gateway into the home for Apple’s growing ecosystem,” Mr Icahn said, including the caveat that Apple “has not announced plans for a TV set and may never do so.”

The idea of Apple making TV sets has long been batted around. So far, the company has only introduced Apple TV, a $100 internet-connected set-top box that lets users stream video from iTunes or Netflix on a television.

Mr Cook has been steadily adding more programming to Apple TV, such as ESPN and HBO, after years of calling it a "hobby."

Apple TV, which was introduced in 2007, competes with the likes of Roku's device, Amazon. com's set-top box and Microsoft's Xbox.

“We think television represents a large opportunity for Apple, one that reaches far beyond ‘the hobby’ that Apple TV currently represents,” Mr Icahn said in the letter.

It’s not the first time that Icahn has suggested that the tech giant build TVs. In a letter to shareholders earlier this year, he said it’s worth considering the possibility of Apple making TV sets as it looks for new products and markets to enter.

Mr Icahn’s projections for TV sets are part of his broader analysis of how Apple’s products, including iPhones, iPads and the new Apple Watch, will accelerate earnings growth.

-Bloomberg