Well-known heavyweight turning up with journalist (5)
I believe the answer is:
noted
'well-known' is the definition.
(I know that well-known can be written as noted)
'heavyweight turning up with journalist' is the wordplay.
'heavyweight' becomes 'ton' (a ton weighs a lot).
'turning up' shows that the letters should be reversed in order.
'with' means one lot of letters go next to another.
'journalist' becomes 'ed' (short for editor).
'ton' reversed gives 'not'.
'not'+'ed'='NOTED'
(Other definitions for noted that I've seen before include "Celebrity" , "Celebrated or recorded" , "Recorded in writing" , "Having renown" , "Significant" .)