Lana Thomas is one of the main antagonists in The Princess Diaries, but it isn't known whether she is the central adversary or not. She is a bully to Mia Thermopolis, the protagonist of the film. Lana is the school mean girl. Lana and two of her friends had embarrassed her in front of a paparazzi, resulting in photos of Mia in nothing but a towel. For this, her defeat is that Mia smears chocolate ice cream on her cheerleading uniform.
Lana is seen at the beginning of the film at Grove high school cheering with her henchmen/best friends Anna and Montana while her lover Josh shows off by scaling the walls of the high school entryway. Later, she is seen making out with her lover Josh whom Mia harbors a crush on and often fantasizes about kissing with. After Mia tries to give a presentation to the entire class about sticking to casual dress code and wearing proper school uniforms, Lana is seen in the crowd with Anna and Montana openly mocking Mia of her appearance, calling her a "fuzz ball" then she and the Lanettes encourage everyone to cheer while Mia runs out of the room to vomit from her stage fright.
After Mia is given a new makeover because her newfound royal heritage but is unable to tell anyone about it, she arrives at school wearing a hat and Lana, seeing this as an opportunity to humiliate Mia, reminds the whole class that hats are forbidden to be worn in the school and Mia is reluctantly asked to remove her hat, debuting her new long lush hairstyle. Seeing this, Lana and her friend decide to once again openly mock Mia of her appearance this time because she is more beautiful then she was previously. Lana sees this new transformation as Mia trying to "fit it" with the popular girls and mocks her, asking her loudly if her new hair is a wig. Lana and her friends are all interrupted by Mia's friend Lily before they are all asked to quiet down and not talk rudely about Mia's appearance, much to Lana's dismay. Later, when Mia arrives at school, Lana and the Lanettes are seen at the top of the school entrance-way outing to the publicity that Mia Thermopolis is the Mia Thermopolis who's a princess. Upon seeing Mia arrive at school with her friends Lily and Michael, Lana wasted little to no time pointing the news reporters at Mia's location and took joy watching Mia suffer at the media and paparazzi overwhelm her with questions. However, when Mia becomes popular by the second of her new "royal" status, Lana decides to up the stakes and try to gain back some of the attention that is overlooked by Mia's popularity, even going far as to lie to a news reporter claiming that she and the princess have been best friends since they were children and that they can sing together, finish each others sentences and other various lies.
After her lover Josh has taken an interest in Mia due to Mia's popularity and beauty and asks her out to the Baker Beach Bash, Lana is infuriated at Josh and Mia's date and makes various attempts to win him back, leading her to sing and perform live with her devoted henchmen The Lanettes. Whilst singing a song that obviously hints at woman's rejection by her suitor for another (hinting at Josh's straying and choosing Mia to date), Lana and her Lanettes see Josh and Mia run along together on the beach having a good time and Lana glares at them from over the shoulder whilst she and her Lanettes receive an outstanding ovation from the crowd due to their musical performance. Having failed to gain Josh's attention, Lana dances with another boy along with the rest of the couples on the dance floor, during which she stares at Mia coldly for being with Josh. Soon, a helicopter arrives at the scene along with the paparazzi to take pictures of Princess Mia at the Baker Beach Bash causing Mia and Josh to take shelter and hide until the media goes away. Seeing this as an opportunity to sabotage Mia's popularity, she and her Lanettes cower around a tent meant for wardrobe changing going over their plan of attack when Mia arrives looking for a place to hide. Lana and her Lanettes lie to Mia, claiming that they hate Josh and want to help Mia. While Lana and her Lanettes manage to win over Mia's trust, Lana takes off to find "help" as she promises while the Lanettes help Mia into the tent and allow her to change out of her clothes as they keep a look-out for any intruders. When Mia asks the Lanettes if anyone was coming to their location, the Lanettes lie, telling her "no". Then Lana arrives guiding the paparazzi to Mia's tent and help her Lanettes knock the the tent over, causing an unclothes Mia to be hoarded by the paparazzi and have her pictures taken unwillingly whilst covered in just a green towel.
As Mia starts to tear up trying to ward off the paparazzi, the P.E. teacher from their school comes to her rescue and whisks her away from the paparazzi to safety. This doesn't impress neither Lana nor her Lanettes as they know their plan to humiliate Mia had been successful and Lana smiles evilly knowing that when Mia returns to school, she would be objectified for her inappropriate moments caught on camera at the beach.
Hey there, ho there, howdy do/This is Grove Lions saying hi to you/Go Lions! ROAR!!
~ Lana and Company performing Grove's signature cheer.
Mia, you are such a FREAK!!!
~ Lana's reaction to Mia, who stands up to Lana and smears ice cream all over her cheerleading outfit.
~ Lana shouting at Mia for ruining her cheerleading uniform, while the crowd openly mocks Lana for bullying Mia.
Miss Gupta, did you see what she's done to me!?
~ Lana's last words as she whines to the principal about Mia embarrassing her.