Old Russian clown is said to die (3,3)
I believe the answer is:
pop off
'die' is the definition.
(I know that die can be written as pop off)
'old russian clown is said' is the wordplay.
'old russian clown' becomes 'popov' (Oleg Popov, 1930-2016).
'is said' indicates a 'sounds like' (homophone) clue.
'popov' is a homophone of 'POP OFF'.
'to' is the link.
(Other definitions for pop off that I've seen before include "Die informally to sound of champagne cork?" , "Die informally like champagne cork?" , "Go" , "Leave without warning" , "exit" .)