The Australian radio show Hot30 has the first ever interview with the newly cast Riley in Eclipse, who will be played by Aussie newcomer Xavier Samuel.

The interview with 25-year old Xavier begins at around 7:30 in the audio, where he confirms that he will indeed play Riley. Here’s what else we learn–

• It’s his first American film role
• He made his initial audition tape in Sydney, then flew to Vancouver and LA to meet the crew, and just found out yesterday that he landed the role
• Xavier watched Twilight for the first time during the plane trip to North America

You can download the show as a podcast in iTunes (Friday July 17th Episode), as an mp3, or listen to a flash version on the Hot30 website.

Xavier tells the Daily Telegraph that he hasn’t started reading the books yet, and plans to begin immediately. He says that–

I’m in a bit of a daze but it’s a wonderful bit of news,” Samuel exclusively told Confidential from Los Angeles last night.

You can also see more photos of Xavier at JustJaredJr.

Check after the break for the official news release from Summit, which is written by Steven Zeitchik of The Hollywood Reporter.

Google might want to brace for a search onslaught: An unknown Australian actor named Xavier Samuel has landed the first new role in “Eclipse,” the third “Twilight” pic.

Summit has hired the actor to play the role of a “newborn vampire” named Riley, a good-looking college student who joins the plot of villain Victoria to murder protagonist Bella (Kristen Stewart). Riley is corrupted by Victoria, for whom he has an inexplicable weakness.

The movie’s larger plot centers on a choice Bella must make between the werewolf Jacob (Taylor Lautner) and the vampire Edward (Robert Pattinson).

Samuel, repped by Management 360, Gersh and Shanahan in Australia, has been in series of films down under, including “Newcastle,” in which he played a Goth teenager amidst a group of surfers (the movie played Tribeca last year — though you can bet Netflix will see just a small spike now), the Aussie period drama “September” and the upcoming sci-fi thriller “Road Train.” This marks his first U.S. role.

“Eclipse,” the third book in Stephenie Meyer’s blockbuster series, is set
to begin shooting next month in Vancouver and be released on June 30. David Slade (“30 Days of Night”) is directing from a screenplay by Melissa Rosenberg.

The Twilight franchise will become the center of the fan universe at Comic-Con next week when the stars of the second pic — the Chris Weitz-directed “New Moon” — appear, new material is unveiled and the crowd goes wild. The Samuel family is probably about to see a little frenzy itself.

[thanks, Elise!]