In 1925 Guitry had the idea of writing a musical comedy about the life of the youthful Wolfgang Amadeus Mozart while in Paris in the 1770s. To compose the score he approached André Messager, with whom he had successfully collaborated in 1923 on a show for Printemps, "L'amour masqué". Messager was unavailable and recommended the young composer Reynaldo Hahn, who accepted the commission. The resulting production, "Mozart", took some liberties with historical accuracy, but it proved highly popular. Printemps, in a breeches role, played and sang the young Mozart, with Guitry as the composer's patron, Baron Grimm. Gielgud recalled, "she seemed ravishingly youthful and touching in her powdered wig, black knee breeches and buckled shoes, while Sacha hovered over her with avuncular authority, not attempting to try to sing himself, but contributing a kind of flowing, rhythmic accompaniment with his speeches, delivered in a deep caressing voice." After playing successfully at the Théâtre Edouard VII, the company presented the piece for a three-week season in London in June and July 1926. The critic James Agate wrote, "It is not exaggerating to say that on Monday evening people were observed to cry, and by that I mean shed tears, when Music's heavenly child appeared at the top of the stairs. At that moment of her entrance this exquisite artist made conquest of the house, and subsequently held it in thrall until the final curtain." After the London production, Guitry took the piece to Broadway, Boston and Montreal in late 1926 and early 1927.