On July 20, 1969, Neil Armstrong and Buzz Aldrin became the first humans to walk on the moon. It was an inspirational moment for people all over the world. But some people are idiots, so they took that inspiration and quickly spun it into a conspiracy theory that NASA faked the whole moon landing on a soundstage

It’s the premise behind Fly Me to the Moon, a romantic comedy starring Scarlett Johansson and Channing Tatum. But even though the conspiracy theory that NASA faked the moon landing is deeply and depressingly cynical, there isn’t an ounce of cynicism in Greg Berlanti’s sweet, comical and joyous film. Fly Me to the Moon uses great screenwriting and good old-fashioned star power to bring a far-fetched concept back down to Earth

Johansson stars as Kelly Jones, a fast-talking advertising executive hired by a mysterious G-man named Moe Berkus (Woody Harrelson) to revitalise America’s crumbling space race propaganda machine. While she’s building buzz through fake interviews and product placement deals, NASA’s launch director Cole Davis (Tatum) builds the whole Apollo 11 spacecraft. He takes his job so seriously that he even flips out when he sees a stray black cat toddling across the Kennedy Space Center, just in case bad luck is real. When his co-workers tell Cole he’s overreacting, he screams, “You’re not overreacting enough!”

Cole is sincere. Kelly is a compulsive liar. They have nothing in common except a shared and seemingly impossible goal: to land American astronauts on the moon. It’s a formula for romantic chemistry that could be taught in science classes, not just in film school. Lesser actors could rest on this premise and get away with it, but Scarlett Johansson and Channing Tatum are on fire. Almost all romantic comedies have a “meet cute” scene, but very few will leave you fanning yourself afterwards. The two characters meet at a roadside diner in Cocoa Beach the night before they’re destined to cross paths at Kennedy Space Center. “You’re on fire,” Cole tells her, and Kelly deflects the line, not realising that, in fact, her notebook is blazing

It sounds like hyperbole to compare Tatum and Johansson to Doris Day and Rock Hudson, but those shoes fit. Johansson’s high-energy vivacity and Tatum’s sad-sack grumpiness make for a beautiful centrepiece. Then Berlanti fills the rest of the film with memorable side characters, like the diva commercial director Lance Vespertine (Jim Rash), and Kelly’s card-carrying feminist assistant Ruby (Anna Garcia). It’s almost hard to believe this film takes place at a maximum security location since every scene gets stolen by somebody.

It’s an inviting place to visit, this version of the 1960s. Although the film is adamant about keeping a light and airy tone, it doesn’t pretend the Vietnam War isn’t happening simultaneously or that President Richard Nixon wasn’t already widely despised. It does, however, pretend that almost no one smoked in the mid-20th century, and that’s as big a lie as the fake moon landing

This screenplay is a difficult balancing act. It probably shouldn’t work but it works practically perfectly. Rose Gilroy wrote the script from a story by Keenan Flynn and Bill Kirstein, and that script segues smartly from frothy romance to teary pathos and back again. Best of all, Fly Me to the Moon cleverly takes its bitter conspiracy theory and treats it like a threat instead of a fact. The mission to put a person on the moon was successful because people believed it could be done. The very idea of faking that mission is such an insult to their achievements that it must be stopped at any cost. With those kinds of stakes, Fly Me to the Moon never feels weightless, no matter how light it comes across

It’s fair to say that Greg Berlanti’s film is more successful when it’s funny than when it’s serious, but it never gets sidetracked by one tone for very long. Instead, Berlanti keeps his film zooming along at a brisk, even breathless clip. Always pressing forward, always shooting off sparks. It’s a rocketship ride of a rom-com