Brussels-born artist André van der Elst, better known as Walli, made his comics debut in Tintin in 1977. He started out with the gag series 'L'Oeuf', and then moved on to draw 'Touky le Toukan' in cooperation with fellow artist Bertrand Dupont from scripts by Bob de Groot. During this period, Walli was also present in the Dutch magazine Eppo with the series 'Kommerkat'.
Also for Tintin, he also succeeded Bertrand Dupont as the artist of the Franquin creation 'Modeste et Pompon' from 1980 to 1987. Together with writer Bom, Walli abandoned the one page gag format of the series, and created several longer stories.
Walli and Bom continued their collaboration with the creation of the series 'Cosmic Connection' in the same year. By 1982, Walli took over the artwork of the classic funny animal series 'Chlorophylle et Minimum', that was created by Raymond Macherot. After an episode written by Bob de Groot, Walli continued the series in cooperation with loyal scriptwriter Bom until 1989. Walli and Bom subsequently created the adventure series 'Gil Sinclair', that was published by Lombard in four books between 1990 and 1994. Since then, Walli has focused on making illustrations for children's books.