Lancel Lannister

Ser Lancel Lannister is a recurring character in the first and second seasons. He is played by guest star Eugene Simon and débuts in "Lord Snow." Lancel Lannister was the squire to King Robert Baratheon and ensured that Robert had plenty of wine during his final hunt. Following Robert's death he becomes the lover of Queen Regent Cersei Lannister, his cousin, and is also elevated to knighthood.

Background
Lancel Lannister is the son of Ser Kevan Lannister and the nephew of Lord Tywin Lannister, the head of House Lannister and Lord of Casterly Rock. He is the first cousin of Jaime, Cersei, and Tyrion Lannister. He has the familial blond hair and resembles his cousin Jaime. He is a squire to King Robert Baratheon.

Season 1
King Robert has Lancel pour wine for him whilst discussing old battles with Ser Barristan Selmy. Robert mocks Lancel's alliterative name, asking if his father had a stutter. Robert becomes annoyed when Lancel runs out of wine and sends him for more. At the Hand's tourney, Lancel tries in vain to help Robert into his armor, tactfully suggesting that it was "made too small". Robert angrily replies that Lancel's mother was a "dumb whore with a fat arse". At this point Eddard enters the tent and bluntly states that Robert's armor doesn't fit, because he has grown too fat for it, to the king's amusement. Robert then sends Lancel out in search for the 'breastplate stretcher' (a nonexistent device). Eddard seems to feel sorry for Lancel, while Robert hopes that he is sent all over camp looking for this thing. Eddard says he should stop torturing Lancel.

Lancel accompanies Robert, Renly and Ser Barristan on a hunt, constantly giving Robert wine. He is present when Robert is mortally wounded by a wild boar. Varys insinuates that Lancel's readiness with the wine may have been deliberate in order to slow Robert's reactions.

While Jaime is being held captive in the Riverlands, Lancel enters into a sexual relationship with his cousin Cersei. The Queen receives news of the war. Lancel questions her about it, he finds it exciting and wants to know what she will do. Cersei is irritated and tells him to stop talking and get back into bed.

Season 2
Lancel attends court in the Iron Throne room following the defeat of Stafford Lannister in the Battle of Oxcross. King Joffrey Baratheon aims an ornate crossbow at Sansa Stark and says that she is there to answer for Robb Stark’s treasons. She denies having any involvement in Robb’s actions, calling Robb a traitor. Joffrey instructs Lancel to tell her of Robb’s latest outrage. Lancel claims that Robb used sorcery and an army of wolves to kill thousands of men under the command of Stafford. He adds that the Northmen feasted on the flesh of the slain after the slaughter drawing cries of outrage and horror from the courtiers. Joffrey orders Ser Meryn Trant of the Kingsguard to beat Sansa but spare her face. Tyrion arrives and halts the torture of Sansa.

Tyrion has had Grand Maester Pycelle arrested for breaking his confidence and feeding information to Queen Regent Cersei Lannister. Cersei sends Lancel to Tyrion with a warrant for the release of Pycelle. He arrives late at night and Tyrion invites him for a drink and Lancel refuses. Tyrion wonders why Cersei did not come herself. Lancel says that he does not care and Tyrion continues to question him. Tyrion establishes that the order came directly from Cersei and then asks why Lancel waited to deliver it. Lancel says that he came immediately and Tyrion wonders what he was doing conferring with Cersei so late at night. Lancel improvises and says that Cersei often works through the night, and Tyrion retorts that she must be glad to have Lancel helping her at all hours. Tyrion notes the scent of lavender oil on his cousin and says that it is a favorite of Cersei. Lancel asserts his position as a knight, and Tyrion jokes that he is an anointed knight. Tyrion asks if Cersei had Lancel knighted before or after she took him into her bed. Lancel furiously calls that a lie, but when Tyrion threatens to tell Joffrey, he collapses into a chair, aghast. Lancel claims that it wasn't his fault, and Tyrion asks if she took him against his will. Lancel insists he was following Tywin’s orders to obey Cersei in all things, but Tyrion counters by asking him if Tywin ordered him to sleep with her as well. Tyrion points out the benefits Lancel has received and threatens to go straight to Joffrey at which Lancel falls to his knees and begs him for mercy and offers to leave the city. Tyrion says that Lancel must act as his spy to buy his silence. Tyrion asks Lancel to beg Cersei’s forgiveness and agrees to release Pycelle but refuses to reinstate him to the council. Bronn stands guard as Tyrion meets with Lancel in a litter on the street’s of King’s Landing. Lancel reveals that the Queen’s plans for defense of the city hinge on the use of Wildfire. Tyrion is disbelieving and threatens to reveal Lancel’s sexual relationship with Cersei to Jaime Lannister. Lancel offers more information to back his claim; Cersei has met with the Alchemists' Guild and they have already stored thousands of pots of the substance. He says that they are planning to launch it from the walls onto Stannis’s fleet and army. Tyrion sees that Lancel is telling the truth and asks when Cersei told him. Lancel says that he has heard Cersei talking with a pyromancer and has visited their guild. Tyrion forces Lancel to swear that his words are true but tires of toying with his cousin and dismisses him. Tyrion kicks him over as he ducks out of the litter and then instructs him to tell Bronn to kill him if anything happens to Tyrion. Lancel dutifully does as he is told. Bronn says that it would be his pleasure as Lancel jogs away. Tyrion uses the information to usurp Cersei's connection to the Alchemists' Guild.

Lancel is on the walls of King's Landing during the Battle of the Blackwater and fights relatively well during a sortie led by Sandor Clegane. However, Lancel is moderately injured when he is shot in the arm by an arrow. Lancel uses the opportunity to retreat from the walls and head back to Cersei to give her a report on the battle. Cersei then drunkenly orders him to go back to the walls and bring Joffrey back to the safety of the Red Keep. Shocked at these orders, Lancel returns to the walls and reluctantly repeats them to Joffrey and Tyrion. Joffrey uses this obvious excuse to make a cowardly retreat from the walls. His soldiers are stunned that their king has abandoned them. When Lancel returns to the Red Keep, he angrily tells her that her order to retrieve Joffrey is costing them the battle, as many of the Gold Cloaks lost heart and abandoned the fight at the sight of their retreating king. Lancel firmly tells her that he must return Joffrey to the walls if they have any hope of rallying their defense again. Cersei flippantly brushes him off, at which Lancel stands up to Cersei for the first time and demands that she listen to what he is saying. In response, Cersei punches the arrow wound in Lancel's arm, causing him to crumple to the ground in severe pain. Cersei storms out of the room as he lies screaming on the floor.

In the books
In the A Song of Ice and Fire novels Lancel is a squire who harbors ambitions to become a great knight. He idolizes his cousin Jaime Lannister. He has the blond hair and general good looks of the Lannisters, but is considered a poor copy of Jaime at best. He is not quite as tall, his features not so fine as Jaime, and unlike Jaime's hair of beaten gold, Lancel's hair is sandy. On the other hand, Tyrion notes, even a poor copy of the famously very beautiful Jaime is still quite handsome.

Lancel has a good and genuinely warm relationship with his father Kevan, as well as with his mother and younger siblings.

Robert Baratheon was talked into taking two Lannister cousins as squires by Cersei in service to her large and ambitious clan, Ned Stark notes. The other squire is 13-year-old Tyrek Lannister who disappears during the Riot of King's Landing.

Lancel doesn't appear in Season 3 of the TV series because he is still recovering from his arrow wound after the Battle of the Blackwater, and thus didn't appear in the first half of the third novel either. The actual wound was relatively moderate but soon festered and developed into a life-threatening infection. Throughout the first half of the third novel other characters such as Tyrion sporadically mention reports that Lancel is very feverish and hovering between life and death.