 John Philip Kemble took over the producer 's ( director 's ) duties at Drury Lane later in 1788 when Sheridan was promoted to chief treasurer . Sheridan often employed Grimaldi in minor roles in Kemble 's productions and continued to allow him to work concurrently at Sadler 's Wells . Grimaldi took an interest in the design and construction of stage scenery and would often help to design sets . His stage performances over the next two years did not garner him the kind of success he had experienced under the management of his father , and the role of pre @-@ eminent Clown in London productions soon fell to Jean @-@ Baptiste Dubois , a versatile French acrobat , horseman , singer and strongman , with a formidable repertoire of comic tricks . Grimaldi worked as Dubois ' assistant , although in later life he denied that he had been the Frenchman 's student . 
