I. co-star¹ /ˈkəʊ stɑː $ ˈkoʊ stɑːr/ noun [countable]
one of two or more famous actors who appear together in a film or play

[TahlilGaran] Dictionary of Contemporary English ▲

II. co-star² verb (past tense and past participle co-starred, present participle co-starring) [intransitive]
to be working in a film or play with other famous actors
co-star with/in
She’s co-starring in a TV version of the 1960s thriller.
He co-starred with Bruce Willis in the movie ‘Die Hard’.

[TahlilGaran] Dictionary of Contemporary English ▲

actor someone who performs in a play or film:
Her son wants to be an actor.
Both my parents are actors.
actress a woman who performs in a play or film. Many women prefer to be called actors rather than actresses:
Who was the actress who played Jane Eyre?
She’s one of my favourite actresses.
star a famous actor:
Julia Roberts is a famous Hollywood star.
The hotel is popular with movie stars.
the star someone who plays the most important part in a play or film:
Daniel Radcliffe is the star of the ‘Harry Potter’ films.
co-star one of two or more famous actors who have important parts in a play or film:
Her co-star Jodie Foster won the Best Actress Award.
the lead the main acting part in a play or film:
He will play the lead in a new version of ‘Dracula’.
extra an actor in a film who does not say anything but is part of a crowd:
She started her career as an extra in TV soap operas.
understudy an actor who learns a part in a play so that they can act the part if the usual actor is ill:
Vanessa had flu, and her place was taken by her understudy, Miss Lisa Fennell.
the cast all the actors in a play or film:
Other members of the cast include Johnny Depp and Danny DeVito.
She will head the cast (=she will have the most important part).
company a group of actors who perform plays together:
In 2006, he joined the Royal Shakespeare Company.
The play will be performed by an all-female company.

[TahlilGaran] English Thesaurus ▲

extra in addition to the usual or standard cost, time, amount etc:
They let the kids stay up an extra hour.
Some stores charge extra for delivery.
Postage is extra.
additional [only before noun] more than the basic amount or the amount that you expected or agreed. Additional is more formal than extra:
An evening job would provide additional income.
There may be an additonal charge for paying bills by credit card.
added [only before noun ] extra – used when talking about something that makes something better or more effective:
an added benefit
an added precaution
It was a beautiful place, and the good weather was an added bonus.
Use a sunscreen for added protection.
spare [only before noun] kept in addition to the one you usually use, so that it is available if the one you usually use breaks, gets lost etc:
a spare key
a spare tyre
a spare set of clothes
actor someone who performs in a play or film:
Her son wants to be an actor.
Both my parents are actors.
actress a woman who performs in a play or film. Many women prefer to be called actors rather than actresses:
Who was the actress who played Jane Eyre?
She’s one of my favourite actresses.
star a famous actor:
Julia Roberts is a famous Hollywood star.
The hotel is popular with movie stars.
the star someone who plays the most important part in a play or film:
Daniel Radcliffe is the star of the ‘Harry Potter’ films.
co-star one of two or more famous actors who have important parts in a play or film:
Her co-star Jodie Foster won the Best Actress Award.
the lead the main acting part in a play or film:
He will play the lead in a new version of ‘Dracula’.
understudy an actor who learns a part in a play so that they can act the part if the usual actor is ill:
Vanessa had flu, and her place was taken by her understudy, Miss Lisa Fennell.

[TahlilGaran] English Thesaurus ▲