Translation:Your sister is a popular actress.
Duo doesn't accept 'actor' - but 'actress' is becoming less acceptable, and more old-fashioned, in many US and UK settings. Just saying ...
We started to accept it, reluctantly, some time ago. Added here. BTW, it was one of only two reports for such an answer.
No, not really. Sure, if you are a popular actress then it most likely means you're also famous, but then you can be 'a popular girl at school' and that doesn't mean you're famous at all. So those are different adjectives even if sometimes they can be very close.