As Ladies Champions announced, so the stars come out (7)
I believe the answer is:
nightly
'so the stars come out' is the definition.
(the stars come out at night)
'as ladies champions announced' is the wordplay.
'as ladies champions' becomes 'knightly' (like knights - knights might rescue ladies).
'announced' indicates a 'sounds like' (homophone) clue.
'knightly' is a homophone of 'NIGHTLY'.
(Other definitions for nightly that I've seen before include "When owls fly" , "(Done) every time it gets dark" , "Every day between sunset and sunrise" , "Regularly during the hours of darkness" , "Nocturnally" .)