I saw this question and realized I've been assuming everyone knows about the main duo from 'Model Behavior'! The central character is Cary, an awkward and brilliant physicist who gets roped into this high-fashion world after his twin brother Connor, a famous supermodel, disappears. Cary's basically forced to impersonate him to keep the business running. He's the ultimate fish-out-of-water, trying to navigate runways and photoshoots with a scientific calculator brain.
Connor is the charming, charismatic twin, but we mostly see him through flashbacks and the immense shadow he casts. His disappearance is the engine of the plot. Then there's Jax, Connor's best friend and fellow model, who becomes Cary's reluctant guide and, of course, the love interest. Jax is skeptical, protective of Connor's legacy, and has that whole wounded, jaded vibe that slowly thaws as he sees Cary's genuine nature.
The roles are pretty classic but fun: Cary is the 'undercover nerd,' Connor is the 'absent star,' and Jax is the 'gruff mentor-to-lover.' The dynamic works because Cary isn't trying to be better than Connor; he's just trying not to blow his cover, which leads to all the comedy and the inevitable moment when his real self becomes more appealing than the facade.
Honestly, I found the side characters like the ruthless agency head, Margot, and Connor's anxious personal assistant, Felix, almost steal the show sometimes. They apply the pressure that makes Cary's performance so tense and hilarious.