"Mereka adalah penyanyi pembuka."

Translation: They are the opening singers.

[atticus.sp]

In colloquial usage, the English would commonly be 'act', not singers (as in 'opening act', 'support act').

[WayangOrang]

'opening act' = 'babak pembuka'.
That is not necessarily about singing.
It could be (for example) an opening act from a ballet performance.

[joeldipops]

I guess you could say "Opening Singing Act"...I'm not sure if that's better than "Opening singers"

[Flanders1]

That is a totally incorrect sentence in English (Australia).

[joeldipops]

"They are the opening singers"? I disagree, it's fine.