Old man initially thanks outgoing film star (3,5)
I believe the answer is:
tom hanks
'old man' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'initially thanks outgoing film star' is the wordplay.
'initially' indicates taking the first letters.
'film' becomes 'M' (h9nh Fritz Lang film).
'star' becomes 'hanks' (I can't justify this - if you can you should believe this answer much more).
The first letters of 'thanks outgoing' is 'to'.
'to'+'m'+'hanks'='TOM HANKS'
Can you help me to learn more?
(Other definitions for tom hanks that I've seen before include "Best Actor Oscar winner 1993, for "Philadelphia"" , "Hollywood star" .)