Wiktionary
co-starring
vb. (present participle of co-star English)
WordNet
co-starring
See co-star
co-star
n. one of two actors who are given equal status as stars in a play or film
v. feature as the co-star in a performance
be the co-star in a performance
[also: co-starring, co-starred]
Usage examples of "co-starring".
Soon I sink into a dream with a familiar theme, co-starring Janet Thrush.
She said she had a co-starring role, and she showed around a viewfinder.