Adam & Eve/DDB created the activity, which uses CGI to bring the boy’s penguin toy to life, in a relationship that evokes Calvin and Hobbes.
The soundtrack is John Lennon’s Real Love, sung by Tom Odell. John Lewis has been trailing the campaign with Channel 4 idents since Monday and the ad will first air on the same channel during Gogglebox tomorrow (Friday).
The spot, which was directed by Dougal Wilson through Blink, ends with the line: "Give someone the Christmas they’ve been dreaming of."
The copywriter was Daniel Fisher and art director was Richard Brim. The computer generated penguin was created by MPC.
John Lewis will sell Monty merchandise – including stuffed toys, onesies and a children’s book – and is opening in-store grottos where Google technology will let children experience Monty’s story in 360-degree virtual reality.
Craig Inglis, the marketing director at John Lewis, said: "At John Lewis, this time of year is all about helping our customers create their dream Christmas.
"We hope this uplifting tale of Sam’s love for his friend Monty will remind people of the magic of Christmas through a child’s eyes and inspire them to think how they can make the festive season extra special for their friends and loved ones."