Spanish runner featured in outside broadcast (4)
I believe the answer is:
ebro
'spanish runner' is the definition.
(Spanish river - a river is something that runs)
'featured in outside broadcast' is the wordplay.
'featured in' indicates a hidden word.
'EBRO' is hidden within 'outside broadcast'.
(Other definitions for ebro that I've seen before include "Spanish river" , "River of northeast Spain" , "foreign river" , "Longest river in Spain" , "Iberian river" .)