Orlando Bloom is 'close to a deal' to reprise Legolas for The Hobbit according to Deadline, the second of the LOTR veterans to return to Middle-Earth after Cate Blanchett's Galadriel - two characters who don't appear in J.R.R. Tolkien's original text. Legolas' appearance clearly makes sense as the character is over a thousand years old, so continuity wise Peter Jackson can easily use the same actor without much trouble. As The One Ring says;
Since Legolas is the son of Thranduil (The Elvenking), a major player in The Hobbit, one can easily see Peter, Phillipa, and Fran writing him into the script. *MINOR SPOILERS* Not only would he appear in Mirkwood with the other wood-elves, he could very well lead the wood-elf contingent into the Battle of Five Armies!Presumably Thranduil, The Elvenking is the role David Tennant has been in talks for, and it's easy to see the resemblance between Bloom and the former Dr. Who. Fleming has been told Bloom's screentime will be 'more than just a cameo' and that talks for Ian McKellen (Gandalf), Andy Serkis (Gollum) and Hugo Weaving (Elrond) whose characters appear in the book, 'have been arduous and aren't completed yet'. Though publicly, Serkis & McKellen have long maintained their commitment, so nobody doubts these talks won't be resolved. Weaving's deal too is surely just a matter of time and can we really imagine Peter Jackson using anyone else but McKellen as Gandalf? We await to hear on Viggo Mortensen (Aragon) or Liv Tyler (Arwen), who aren't human characters and are surely the only other two major characters from LOTR who could appear in this. Right? Or am I forgetting anyone?