Yesterday ★★

If not for an endearing cast and some occasional splashes of Richard Curtis’ signature British charm, “Yesterday” would be a complete waste of its clever premise — not to mention the money it must have cost to license 17 of the Beatles’ most famous songs. As it stands, this sweet but vacuous exercise in suspending disbelief is an overstuffed and underwritten misfire; a studio-engineered crowd-pleaser so convinced “All You Need Is Love” that it loses sight of some other essentials along the way: Believable characters, elegant pacing, a script that develops an actual heart instead of just nodding its head to a steady drumbeat of Hallmark emotions. For a movie that manages to inspire a funny and self-effacing performance from Ed Sheeran, “Yesterday” gets tripped up on the basics.

The premise, dreamed up by one-time “The Simpsons” writer Jack Barth, is ingenious for how specifically it taps into a fantasy that should be familiar to anyone who’s ever longed to create something as miraculous as their favorite music. It begins with Jack Malik (golden-voiced “Eastenders” star Himesh Patel, talented as no tomorrow but handicapped by a one-note role in his big-screen debut), a struggling musician who’s this close to giving up on his dreams of fame and fortune. After 10 years of busking on the streets and playing the same few bars in Sussex, he’s one lousy gig away from putting his guitar away and becoming a teacher. The only person more disappointed in Jack than he is in himself is his best friend and biggest fan, Ellie (Lily James, winsome as ever), the beautiful girl next door whose single-minded crush on him has grown so large that it flattens them both into two-dimensional characters.