I'd like to take part in ballet sometime (4)
I believe the answer is:
lets
'i'd like to' is the definition.
'part in ballet sometime' is the wordplay.
'part in' indicates the answer is hidden within the clue.
'LETS' is hidden in the letters of 'ballet sometime'.
'take' is the link.
(Other definitions for lets that I've seen before include "Permits" , "Yes" , "Rents out or allows" , "Leases" , "Allows or causes to" .)