That's what Viggo Mortensen told ComingSoon.net,

"My character is around at times--in the middle, but it would only be if they made a second movie or connecting movie that connected 'The Hobbit' to 'The Lord of the Rings' that I might appear, which would be great."

It was relatively well known that when Guillermo Del Toro and Peter Jackson first started working on their two Hobbit films they wanted to secure as much of the original cast as possible and feasible (for story purposes). The reason for this; the second film was going to be a bridging film between The Hobbit and The Lord of the Rings, what Mortensen eludes to in the above quote. It was assumed we might find out some back story on some of our favourite characters, possibly act as a bit of fan service, and this would add to the original Lord of the Rings experience. With that in mind hearing Mortensen say he was interested in a role in the second film would be great and wouldn't sound ridiculous, as his character Aragorn certainly had a lot of mystery surrounding him and he was probably many a fan's favourtie (mine included).

Thing is, in recent weeks, Jackson and Del Toro have expressed their desire to change the focus of the second film. Instead of the first film focusing solely on the book, The Hobbit, and the second bridging the two stories they have now decided to use both films to tell the story of The Hobbit, which means it's unlikely we will see Aragorn again as he does not actually feature in the book. The only way we might see Aragorn is if they write him in. While The Hobbit takes place 50 years before The Lord of the Rings Aragorn would certainly appear much the same as he did in the original trilogy. From what I remember of the extended second movie and from what I've read from devoted Rings fans Aragorn is part of a special race, a mixture of man and elf, that have the gift of extended life. Basically they age way slower than anyone else. So while he lets it slip that he is 85 in the second film, and looking good I must say, it would make him 35 during the time of The Hobbit.

So what do you think of existing characters, like Aragorn, returning to the series? Is it a ridiculous idea that will ruin the integrity of the books?  Or will it provide enough recognition for peripheral fans of the original series to see the new movies? Personally I'm happy with Sir Ian McKellen returning as Gandalf and would be happy to see Christopher Lee as Saruman but outside of seeing Aragorn in a bridging movie I think it might ruin it if he was in the actual Hobbit and I think Mortensen realises that.