Complex sentence: Burr was starring in a series of Perry Mason TV movies at the time, so in order to make himself look less like the other character, he dyed his hair and modified his full beard to a goatee for the "Ironside" movie.
Split into simpler sentences: Burr was starring in a series of Perry Mason TV movies at the time. In order to make himself look less like the other character, he dyed his hair and modified his full beard to a goatee for the "Ironside" movie.