Internet video company Hulu expects its number of paid subscribers to top 1 million by summer's end, earlier than previously forecast, its chief executive said on Wednesday.

We are extremely encouraged by the ramp of this business, Chief Executive Jason Kilar said on the company's blog. Hulu previously forecast reaching that level by the end of the year.

The company remains on track to approach half a billion in 2011 revenue, Kilar added.

Hulu is owned by Comcast Corp's NBC Universal, News Corp, Walt Disney and Providence Equity Partners. The company has begun preliminary sales talks with about a dozen potential buyers, including Google Inc and Microsoft Corp, a source familiar with the situation said last week.

Hulu offers free online access to prime time television shows such as The Office. The paid Hulu Plus service, introduced in November, offers a broader range of content for $7.99 per month. The company also makes money from advertising.

Hulu generated the largest share of U.S. online video advertising revenue in the second quarter, Kilar said.

Though Hulu is popular, its owners are under pressure from cable and satellite companies that are reluctant to pay top dollar to carry programing offered for free on the Web.

In addition, many programmers are unwilling to put their shows on a free site with an advertising model that has yet to prove itself with premium video.

Hulu's largest competitor is Netflix Inc, which has more than 20 million paying subscribers in the United States. Netflix announced on Tuesday it was expanding into Latin America and the Caribbean.

(Reporting by Lisa Richwine. Editing by Robert MacMillan and Matthew Lewis)