Sony on Tuesday announced a hotly-anticipated streaming game service along with the news that it sold more than 4.2 million PlayStation 4 consoles by the start of this year.

PlayStation Now, set to begin a test phase this month and launch in the United States mid-year, promised to let gamers access blockbuster titles in the Internet "cloud" and play them on an array of devices intended to expand over time.

The new streaming game service will provide PlayStation gamers access to games they love from prior generation consoles and grow to extend play to other Internet linked devices such as smartphones and tablets, according to Sony Computer Entertainment president Andrew House.

A lament of gamers shifting to new-generation consoles is that the devices don't play games tailored for earlier models. Sony's service will begin by providing hit titles for play on PS4 and PS3 consoles, and then the Japanese entertainment titan's handheld Vita game devices.

"We are thrilled to deliver entertainment experiences only possible from PlayStation through our new streaming game service," said House.

Sony was demonstrating the service on some Bravia smart television models at its booth at the Consumer Electronics Show, which will continue here through Friday.

The goal of the service is to let people "play where ever they want, when ever they want" and incorporates technology from cloud gaming company Gaikai, which Sony bought in 2012 for $380 million.

Gamers will be able to rent titles at Play/Station Now or pay for monthly subscriptions to the service, according to House.

House updated PlayStation 4 sales figures to say that 4.2 million consoles had been sold as of December 28 of last year. Sony launched the PS4 in on November 15.

Sony Entertainment Network will begin testing later this year a cloud-based television service in the United States, according to House.

The service will combine popular live television programs with a large library of on-demand content, according to Sony. Shows or films will stream to an array of devices, including tablets or smartphones made by competitors.

House heralded the new television service as a natural evolution of Sony's moves to combine strengths in entertainment, gaming and consumer electronics.

Pricing details for the gaming and television services were not revealed.