Barcelona brings two television stars to the stage, with Lynette Linton directing Money Heist’s Álvaro Morte and Emily in Paris’ Lily Collins for a night of sex, sadness, and American exceptionalism.

The Sagrada Familia looks better in the guidebook, slurs Emily In Paris star Lily Collins as she drunkenly stumbles into the apartment of a suave Spanish stranger. Her character – painful epitome of an all-American tourist in her Coke Zero can of a sequined jumpsuit and questionably blasé outlook on Western interventionism – is in Barcelona for a bachelorette party. She drank too much sangria, ate too much tapas (she’s ‘really into’ tapas), and ended up going home with Mañuel (who she calls Manolo, like Carrie Bradshaw’s favourite shoe designer). Her own shoe, for what it’s worth, is missing: she threw her heel at Mañuel’s head before they left the bar.

Bess Wohl’s Barcelona, currently at the Duke of York’s theatre, starts out like so many rom coms do, mining easy laughs from the culture clash of unthinking American and macho European heartthrobs. Lily Collins’ Irene is a Denver dumb blonde, and Álvaro Morte plays Mañuel as a reactionary anti-American who louches around with his unbuttoned shirt and rioja-smelling disdain. Their drunken meet cute – everything is ‘cute’ for Irene: the apartment, the man, Spain – is the stuff of Gen-Z Henry James. He plays her Puccini, she twerks to Ludacris. He kisses her ankles, she throws up in the broken loo. Her idea of Barcelona comes from a commercial for Spanish (‘wait, maybe it was Mexican’) beer, and his mental image of America is Paris Hilton and genocidal pilgrims.

But soon Barcelona stops being all that romantic, and certainly stops being a comedy. Whol’s script drip feed us revelations: That bachelorette party? It was Irene’s, she’s on the first flight home to get married. The plumbing in Mañuel’s bathroom isn’t working because the apartment, whose real owner is a major plot point, is due to be demolished at dawn. The play is set in 2012, and makes a solid go of interrogating Obama-era American optimism. A conversation about American exceptionalism and 9/11 reveals that Mañuel has a strangely visceral emotional response to a recent terrorist attack in Madrid, and things begin to fall apart.

The set follows suit. Jai Morjaria’s lighting serves as a psychological litmus test throughout Barcelona. At first, the chiaroscuro of midnight blue and warm orange street lamps promises the romance of a Van Gogh café. Soon, though, the dappled sunrise curdles into a lurid yellow as Mañuel explains the real reason he’s squatting amid frilly curtains and fairy lights. There’s more than meets the bedroom eyes for the hunky lothario. Ghostly shadows of flamenco dancers flicker across the walls like flames; lights in the bathroom switch on, unexplained. Suddenly, we’ve reached Emily In Paris as told by Tennessee Williams. Both characters have been lying. Both are tourists in their own lives. And they’re definitely not going to sleep together.

Barcelona is a play of slow reveals and lingering questions. But what audiences really want to know is how Lily Collins fares in her West End debut. Crowds have lined the streets to catch a glimpse of the star at the stage door, and countless column inches have been dedicated to her theatreland introduction. It’s clear to see why she was cast: Irene is the archetypal American abroad à la Emily in Paris. Collins glitters with A-list television star charisma on stage, bringing old Hollywood charm to a character who seems nothing more than a ditzy would-be bride whose cold feet can’t be blamed on her missing high heels.

But there is more to Irene than her Black Eyed Peas ringtone. Collins radiates panic and relief in equal measure as Irene realises that no, she probably doesn’t love her moralistic town pastor fiancé quite as much as she thinks she does. She conjures frustration and ennui recounting a life spent stuck in the most all-American of contradictions. Irene is an American, and Americans can do anything – but she’s trapped in a domestic purgatory, proud of her pilgrim ancestors but unable to navigate home without an iPhone. Collins does wistful well, too, especially when confessing to Mañuel that her only escape in life is to pretend that she lives in the houses she sells as an estate agent, offering non-existent canapes to phantom dinner guests. She’s sad, but she’s no sap, and if there’s one thing her job has taught her, it’s how to help people pack up and move on…

So, Emily in Paris has done some growing up in Barcelona, and Lily Collins has established herself as a West End star in the making. As Irene and Mañuel catch a last glimpse outside the apartment window, the sun finally risen on their borrowed time, they look out onto Barcelona, a wrecking ball, and the Sagrada Familia. The unfinished cathedral, Irene says, is a monument to perseverance. They say it’s a must-see.