Seen in bit parts in other films, she popped in “Booksmart” and now has a chance to stretch in “How to Build a Girl.”

One of the films that took advantage of at-home viewing this year, “Girl” follows a bookish British teen looking to break out of her dull life.

Winning a contest (to work for a rock magazine), Feldstein’s character reinvents herself as Dolly Wilde, a magenta-haired free spirit who makes a name for herself with buzzworthy reviews.

Sensing her worth, she pushes and gets an opportunity to do a feature on a rocker (Alfie Allen) and a window onto a world she never knew.

The story is a disaster. Her smarmy bosses spike it and the fallout sends her reeling.

Like “Almost Famous,” “Girl” tries to show the heady world the young writer encounters. Director Coky Giedroyc gets the office atmosphere right, but totally lets Feldstein’s naif flounder in those dark clubs. It’s clear where this is headed, but it doesn’t explain why she isn’t given literary obstacles.

Luckily, Feldstein has what it takes to make the frenetic lifestyle work. She gets the accent (which is a bit of a stumbling block at first), she nails the attitude. Even when she’s calling out her parents for relying on her income (which must be substantial), she sells it.