His first "acting" role was as a baby. In the 1981 BBC radio version of "Lord of the Rings", Harry's crying was used for the role of Elanor Gamgee, the daughter of Samwise. Harry's father,
Ian Holm, starred as Frodo in the same production (and later as Bilbo in the "Lord of the Rings" and "Hobbit" film trilogies).