From EW:

When the second and third installments of the Hobbit trilogy, The Desolation of Smaug (out Dec. 13, 2013) and There and Back Again (out July 18, 2014), arrive in theaters, we’ll encounter some familiar faces as well as some new ones as Bilbo and the dwarves continue their perilous journey to the Lonely Mountain, home of the dragon Smaug. One familiar face will be Orlando Bloom’s elf Legolas, a major character in the Rings trilogy but one not mentioned in the Hobbit book. (Cinema, The Hobbit: There and Back Again)