Peter Jackson’s The Hobbit: An Unexpected Journey is a prequel to his Lord of the Rings trilogy, which most people rushing to The Hobbit will have already seen. In the new film there are many nods or foreshadowing to adventures or characters seen in LOTR, and connections to be made. But if you are not an obsessive Tolkien-head or haven’t recently rewatched the earlier films, they may go over your heads. Here is a list of references big and small in this first entry of the new Hobbit trilogy that were presaged in the LOTR films. (Wait, not presaged: What do you call foreshadowing if it’s to a prequel? Post-saged? What is this, Looper?)
The Hobbit takes place 60 years before the Lord of the Rings adventure, save for the new film's prologue, which unfolds about twenty minutes before The Fellowship of the Ring begins. In it, Elijah Wood returns as Frodo to chat with old Bilbo (Ian Holm) about the elder Hobbit's upcoming 111th birthday party — the one that Gandalf arrives for at the beginning of Fellowship. In this Hobbit prologue, Bilbo is procrastinating his party prep by working on his memoir, There and Back Again, which is also the subtitle of J.R.R. Tolkien's book The Hobbit. Bilbo tells Frodo that his greatest party-related fear is an unwanted appearance by his distant relatives, the hated Sackville-Bagginses — who, you'll recall, do show up in the party in Fellowship.
In Fellowship, Gandalf talked to Frodo about his habit of taking Hobbits on great adventures: "If you're referring to the incident with the dragon," Gandalf said, "I was barely involved. All I did was give your uncle [Bilbo] a nudge out the door." The Hobbit essentially is that incident, and the movie will show that the word “nudge” is a bit of a euphemism.
In Fellowship, Gandalf referred to Pippin as a "Fool of a Took" when, in Moria, he knocked a skeleton and gear very noisily down a well, alerting the orcs. And since Merry and especially Pippin started off as comedic relief in Fellowship, it left the impression that the Took line is notorious for its foolishness. But as we learn in The Hobbit, Gandalf used to have a much more favorable opinion of the Tooks: He recruits Bilbo for the movie’s central quest — to help a band of exiled dwarves retake their homeland from dragon Smaug — because Bilbo’s mother Belladonna was a Took, who Gandalf says are always game for an adventure.
Gloin is one of the thirteen dwarves who take Bilbo on their quest. He is the father of Gimli, who was played by John Rhys-Davies in LOTR. Gloin plays a major part in The Hobbit — and he's carrying the big axe that he'll later hand down to his son for use in the Rings films.
You may recall that en route to Moria in Fellowship, Gimli promised his companions that his cousin Balin would give them all "a royal welcome." What they actually found there, though, was death and dust, and a musty old tome about the fall of Moria written by a Dwarf named Ori. Balin and Ori are both very much alive in The Hobbit, and loyal followers of the Dwarf king Thorin (Richard Armitage).
In Fellowship, Gimli was deeply resentful of Orlando Bloom’s Elf prince Legolas ("Never trust an Elf!"). This hostility will be explained later in the trilogy when we’ll see the tension between their respective dads, Gloin and Elven king Thranduil (played by Lincoln’s Lee Pace). We only glancingly get to see Thranduil in An Unexpected Journey, but the relationship will be expounded upon in future installments, as we will also see the return of Legolas (Lee Pace promised us at the New York premiere that there will be major scenes with Orlando Bloom in the subsequent films).
At Bilbo’s birthday party in Fellowship, Bilbo wowed some kids with a tale of his old adventuring days: "And so there I was, at the mercy of three monstrous trolls, and all arguing amongst themselves about how they were going to cook us!" That was not a tall tale — and we see it at considerable length in The Hobbit.
Frodo inherited the orc-detecting sword Sting along with a Mithril mail shirt (a sort of Middle-earth Kevlar) while in Rivendell. "This is Sting. You've seen it before, haven't you?" he said to Gollum in The Two Towers. Yes, Gollum definitely had, and that introduction is made in The Hobbit, where we also learn how Bilbo acquired these life-saving treasures in the first place.
The Ringwraiths (or Nazgûl) wielded deadly blades in all three LOTR films; Frodo was nearly made into a wraith himself when he was stabbed with one. When Gandalf brings one of these Morgul blades to the White Council in The Hobbit, it alerts them to a danger that they thought was sleeping.
Shelob, the giant spider who lives in the secret way to Mordor in Return of the King, likes to trap halflings in her webs: Sam nearly lost Frodo to her venom, and had to take the Ring himself for a bit. You’ll spot her kids in An Unexpected Journey, and spend some quality time with them in next year’s part 2, The Desolation of Smaug.
And finally, what would a Hobbit movie be without the One Ring, Gollum's Precious? In the earlier trilogy, the devious homunculus berated Hobbits as thieves for having made off with it, and pointed dark forces in the direction of the Shire. The riddle of how this ring-based grudge began will be solved.