Complex sentence: Sheen had made his film debut in Frears' "Mary Reilly" (1996), and although he was unsure whether his minor role had "burned into (Frears') brain", Frears confirmed that Sheen had remembered from that.
Split into simpler sentences: Sheen had made his film debut in Frears' "Mary Reilly" (1996). Although Sheen was unsure whether his minor role had "burned into (Frears') brain", Frears confirmed that he had remembered from that.