Joined me on the tee (3)
I believe the answer is:
met
'joined' is the definition.
(meeting is a kind of joining)
'me on the tee' is the wordplay.
'on' says to put letters next to each other (in a down clue, letters appear on others).
'the tee' becomes 't'.
'me'+'t'='MET'
(Other definitions for met that I've seen before include "satisfied" , "Encountered by chance or arrangement" , "Came together, encountered" , "Bumped into" , "Got together" .)