Video streaming pioneer Netflix Inc added more subscribers in the first quarter than it had projected, helped by aggressive expansion in overseas markets.

Shares of Netflix, which shook up internet television with original shows such as "House of Cards", rose about 13 percent after the bell on Wednesday.

Net subscriber additions rose 22 percent year-over-year to 4.88 million in the first quarter ended March 31, beating its own forecast of 4.05 million.

The company has been aggressively building its overseas presence to make up for slowing growth in the United States. It launched services in Australia and New Zealand in the quarter and expects to start in Japan later this year.

Netflix added 2.6 million customers in its nearly 50 international markets in the quarter ended March 31, bringing the total to 62.27 million users worldwide.

The company said it expects to sign up 600,000 more customers in the United States in the current quarter. It forecast adding 2.5 million subscribers worldwide in the quarter.

The company has also been investing in original shows to fend off competition from Time Warner Inc's HBO, Amazon.com and Hulu, as well as on-demand offerings from pay TV providers.

Netflix, whose stock has traded above $300 for more than a year-and-a-half, also said it would seek board approval for a stock split.

Revenue rose to $1.57 billion from $1.27 billion a year earlier. (bit.ly/1JL8nFk)

Increased spending on international expansion hit first- quarter earnings, which more than halved to $23.7 million, or 38 cents per share.

Excluding items, the company earned 77 cents per share.

Analysts on average had expected a profit of 69 cents per share on revenue of $1.57 billion, according to Thomson Reuters I/B/E/S.