Its racy title notwithstanding, “Juliet, Naked” is not salacious but delicious. A charming film of an engaging, adult nature about two very different people trying to press reset in their lives, it is comic, heartfelt and smart as they come — a rare combination these days.

Impressively directed with feeling for the material by Jesse Peretz, “Juliet, Naked” is acted with verve, passion and great skill by a cast toplined by Rose Byrne, Ethan Hawke and Chris O’Dowd, all doing impeccable work.

Looming equally large as a creative force is Nick Hornby, author of the original book as well as the novels that inspired “High Fidelity” and “About a Boy.”

Although Hornby wrote the adaptations of acclaimed period pieces “An Education” and “Brooklyn,” no one is better at comically exploring the modern condition, at reflecting how we live now.

Hornby has been well-served here by screenwriters Evegenia Peretz and Jim Taylor & Tamara Jenkins, who’ve made expert use of his superb ear for dialogue and gift for playful situations that make you laugh while clandestinely engaging your deeper feelings.

“Juliet, Naked” begins by having its two protagonists essentially introduce themselves on-screen.

Up first is Duncan (the brilliantly comic O’Dowd), a Brit who redefines the limits of musical obsession by being the world’s biggest fan of a man he considers “the most underappreciated figure in rock history.”

That would be cult favorite Tucker Crowe, an American singer-songwriter who recorded a dazzling album called “Juliet” and then completely dropped from sight decades ago after an abortive show at a decrepit Minneapolis club called the Pit.

A smug and self-absorbed academic who teaches courses like American Cinema and the Alienated Male at the university in fictitious Sandcliff, a down-at-the-heels British resort town, Duncan admits being “a little overzealous.” But his obliviousness to how bonkers he is is part of the film’s charm.

Duncan’s partner of 15 years is the sane and self-aware Annie (Byrne, letter perfect), heard in voice-over as she walks through town bemoaning her fate.

Annie left a promising career in London to return to Sandcliff to tend to her dying father, but her life of running the same local history museum he did is beginning to seem like a trap.

Though initially dazzled by Duncan’s glibness, Annie has become disenchanted with the way “his obsessions dominate my life.” Though she initially agreed with Duncan’s desire not to have children, she is intensely regretting that decision and having “traded unconditional love for conditional affection.”

Tired as well of being the sensible one in her circle, which includes a wacky sister (stand-up comic Lily Brazier) with dreadful romantic instincts, Annie has no idea how to change her life until an unexpected package arrives at the house she and Duncan share.

Pretentiously labeled “Juliet, Naked,” it’s nothing less than the acoustic demo versions of the album that Duncan reveres as one of the great works of Western civilization.

Not being in the best of moods, Annie does not take to the new tunes the way her partner does, and in a beautifully set-up series of events, writes a disparaging review of it for Duncan’s fan website.

Duncan, of course, is not happy, but someone else is. Unbeknownst to anyone but herself, Annie’s email has caught the attention of the real Crowe, who writes her back, which is where “Juliet, Naked” kicks into a higher gear.

Perfectly played by Hawke, who has never been more casually charming (which is saying a lot), Crowe turns out to be a feckless ex-rocker with numerous kids from several mothers who has always run the other way when responsibility was called for.

Now living in a garage behind the home of one of his exes, he is trying to turn over a new leaf with his youngest child, 6-year-old Jackson (a genuinely endearing Azhy Robertson).

More than that, he turns out to be a completely engaging email correspondent, and he and Annie (who has understandably kept all this hidden from Duncan) are soon confiding in each other left and right.

Inevitably, circumstances conspire to bring Tucker to Britain, but how the unavoidable meeting with Annie happens and the way the complex and completely unexpected ramifications of that play out are a treat to behold.

Not only has director Peretz ensured that the characters are both amusing and emotionally resonant, but he’s also used his experience as a founding member of the band Lemonheads to ensure that Tucker’s songs (Hawke sings them all, plus a version of the Kinks’ “Waterloo Sunset”) are convincing as well. As a playful romantic triangle with a shape all its own, “Juliet, Naked” shouldn’t be missed.

“JULIET, NAKED”

****

(R, 1:45)