I really like the suggestion of Charlie Cox, but at the same time it will be a little overkill with the Stardust connection (Barnes/Cox). And the film makers want to avoid that.
I have a really great candidate here, which everybody else has forgot to mention. It's Rollo Weeks. Strange that no-one didn't even think about him.
So, I give you ROLLO WEEKS as Prins Rillian.

^ I agree that Rollo Weeks belongs in Narnia! I just imagine Rilian to be played by someone the same age as Ben Barnes is right now, but if he can appear older that would be very great. Rollo would also make a great King Tirian though!

Has anyone considered Josh Hutcherson yet?

~Riella

^He's too young for the role. There's a ten year range of Rilian's disappearance. He was at least 17-19 years of age when his mother died and fell under LOGK's enchantment. Actors ages 27-32 would be more ideal for Rilian.

I think Harry Lloyd would do well.

stateofgreen, I agree. He's one of my favorite actors, especially in the Robin Hood series. I would love it if he took the role, but I wouldn't be too upset if someone else got it. I pretty much trust the Narnia casting directors by now; I've been happy with their choices so far.

Yes. I still like Harry Lloyd for the part of Rilian. He was also most popular in a poll we did on the old NarniaWeb forum. Link to previous post with poll results:
http://forum.narniaweb.com/viewtopic.php?f=3&t=1177#p60744

However, as MountainFireflower pointed out (and I agree), the casting choices overall for the Narnia movies have been pretty good overall. But they can still come here before they decide and consider our recommendations too.

having just seen the new Sherlock Holmes(which is a pretty good movie) movie I think Hans Matheson who's been mentioned before would make a pretty good Rilian, I liked his acting in Sherlock Holmes even though he was a villain and he is probably my number 1 choice for the Rilian role.

he also has to look like he could be bens son grown up some of these are good sugestions but they don't look like ben except the post on the first page where someone suggested they young guy from inkheart he looks like he could be bens son grown up

What about Elijah Wood? (Ok, I'm kidding...then again...hmmm...)

Maybe he would work!

*ducks tomatoes, chuckling LotR fan chuckle*

"What about Elijah Wood? (Ok, I'm kidding...then again...hmmm...)"

actually I've had the same thought myself...though I tend to lean more towards Orlando Bloom. I think Bloom looks like he could be related to Barnes, is definately oldmature enough, has the acting skills, and would lend some star power to a movie that might desperatly need it. Downsides would be his price, and maybe the fact that he's already had two iconic roles. But I think it's time one of the Narnia movies had a bigger star in them, might help out that neverforgotten box office totals

Hey, good idea! Of course, Elijah Wood would lend a more mysterious piece to the role, but Orlando Bloom would look more like Caspian. I'd be thrilled to pieces for either one!

Plus, as far as the star-thing goes, I don't mind if they make sure we don't exactly have Frodo or Legolas on our hands. It'd be good for the series!

Lu

You can add me to the list of "I-watched-Sherlock-Holmes-last-night-and-think-Hans-Matheson-would-make-an-awesome-Rilian" people.

I hadn't realized he had been suggested already but when I came on here today to do so, I noticed several people already had. And I remember reading those posts, but he looked different enough in Sherlock Holmes that I didn't recognize him from here. Something about him in Sherlock Holmes must have really screamed Rilian.

At any rate, I agree with this suggestion!

I rather an unknown played Rilian. He definitely needs to look like or simular to Ben Barnes with a tad look to Lilliandil like her face shape or have blue eyes.

I know that this guy is one of my candidates for Tirian but the more i look at his imdb profile picture the more I see a lot of ben barnes in him and some appearances like eye color that he could get from lilliandil.

He's a bit younger then how Rilian should be too but he can pull it off I think:

http://www.imdb.com/name/nm0020264/