Bert's "Sesame Street" buddy (5)
I believe the answer is:
ernie
'bert's sesame street buddy' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ernie that I've seen before include "Sergeant Bilko, for one" , "Selector of winning premium bond numbers" , "- - Bevin, 13 dn" , "Premium Bond selecting machine" , "___ Wise, d. 1999" .)