Teletubby twice to regret making comeback to make catchy music (7)
I believe the answer is:
europop
'catchy music' is the definition.
(type of pop music)
'teletubby twice to regret making comeback' is the wordplay.
'teletubby' becomes 'po' (character in the children's TV show Teletubbies).
'twice' becomes 'po' (I can't justify this - if you can you should give a lot more credence to this answer).
'to regret' becomes 'rue' (to rue something is to regret it).
'making comeback' says the letters should be written in reverse.
'po'+'po'+'rue'='poporue'
'poporue' in reverse letter order is 'EUROPOP'.
'to make' is the link.
(Another definition for europop that I've seen is " music".)