Hulu, the popular online video service which has been put up for sale by its joint owners, now has more than 1 million paying subscribers, Chief Executive Jason Kilar said on Wednesday.

Earlier this year Kilar forecast that Hulu would have 1 million subscribers by the end of the year. He confirmed that it reached that milestone at the end of the summer and the site is now on its way to easily exceed that number by year's end.

The site made its name as a free service for popular broadcast TV shows like The Office and Modern Family soon after the shows had been aired.

The shows and movies it initially featured were supplied by its joint equity owners News Corp, Walt Disney Co and Comcast Corp's NBC Universal. Its fourth co-owner is private equity firm Providence Equity Partners.

Hulu launched a subscription tier last November and has since added more content from partners including Viacom and Hollywood studio Miramax.

Kilar said customers' preference for TV shows and library content on Hulu and Netflix Inc is a function of the deals the sites are able to reach with programmers within the constraints of their respective financial models.

We will invest over $375 million in content this year, said Kilar, speaking at a Goldman Sachs investor conference.

Kilar has previously said the company will have around $500 million in revenue this year.

Some programmers have been reluctant to do major U.S. deals with Hulu due to concerns that it might undercut their relationships with pay-TV distributors. CBS Corp boss Les Moonves in particular has been the most vocal about his caution with Hulu, even though his company inked a deal with Hulu in Japan.

I'm cautiously optimistic that we'll work with everyone over time, Kilar said.

Kilar was complementary about the risks Hulu's owners had taken in setting up and supporting the business to date even though those owners put Hulu up for sale earlier this year.

Reuters reported last week that the $2 billion sale had hit speed bumps in recent weeks as the owners reconsidered whether a sale is still the best strategy.

We're still evaluating the situation, said News Corp Chief Operating Officer Chase Carey, speaking to Reuters on the sidelines of the conference -- reiterating recent comments on a quarterly earnings call. He declined to comment further.

Earlier in the summer Disney CEO Bob Iger had said the owners were fully committed to selling Hulu.

NBC Universal is not actively involved in the sale process. Comcast agreed NBC Universal would not participate in management decisions of Hulu in order to receive regulatory approval for its takeover of the broadcaster and cable giant.

Critics of the plan to sell Hulu argue the owners should keep hold of a major distribution channel of the future rather than sell to possible new owners like Google, or Yahoo.

(Reporting by Yinka Adegoke; Editing by Phil Berlowitz)