Showtime is putting the second-season premiere episode of its series “The Tudors” on YouTube, starting tomorrow.

The episode doesn’t air on Showtime until Sunday.

The move is part of Showtime’s digital push to introduce people to the show and persuade them to subscribe to the CBS-owned pay cable series.

“We’re only in 15.5 million homes. We need to find a way to get people to sample it,” said Rob Hayes, senior VP and general manager of Showtime Digital Media.

While most Web promotion of TV series consists of clips, Showtime has been a big believer in streaming full episodes of shows, going back to when it put “Fat Actress” on Yahoo.com a few years ago.

Whether YouTube users, accustomed to grazing through a menu of short videos, will sit still for an hourlong presentation is unknown.

“It will be interesting to see how it plays out on that platform,” Mr. Hayes said.

Showtime has been aggressive in digital media and has seen results. After digital promotions, the network sees a spike in usage of the “order” area on its Web site, Sho.com, as well as added calls to its 800 number.

“In the past it’s been very effective,” Mr. Hayes said.

In addition to YouTube, Showtime is making the episode available to 60 online platforms with a combined reach of 190 million users. Sites including Yahoo, MSN, AOL, Netflix and Amazon’s Unbox began showing the premiere a week ago. It’s also available through cable and satellite affiliate Web sites, iTunes and the CBS Audience Network.

And for mobile users, Showtime is making the episode available to Verizon Wireless subscribers via VCast.

Promos attached to the video drive viewers to Showtime’s Web site. There’s also an 800 number for users who would rather use the phone to order the network.