Around this time, he became a stage painter for a theatre adaptation for Hergé's "Cigars of the Pharaoh". This led to friendship with Hergé. As a direct result, he helped Hergé in colorizing the black and white strips of "The Shooting Star" to be ready for book publication in 1942. From 1944 on he helped in the recasting of his earlier albums "Tintin in the Congo", "Tintin in America", "King Ottokar's Sceptre" and "The Blue Lotus" for color book publication. After the project, he continued to contribute directly in the drawing as well as the storyline for the new Tintin double-albums "The Seven Crystal Balls"/"Prisoners of the Sun".