The main actor is excellent.
pro-ta-go-NI-sta — stress on fourth syllable. Five syllables total.
Comment on a performer's skill during post-film discussion. Works for both male and female leads — 'protagonista' is grammatically masculine but used for both. Very common in Italian film conversation.
'Protagonista' means main character or lead actor. 'Bravissimo' is the superlative of 'bravo' (good/skilled). In Italian, 'bravo' applied to an artist specifically means technically skilled, not just nice. A 'bravo attore' is a skilled, accomplished actor.
L'attrice principale è straordinaria.
The main actress is extraordinary.
Uses 'attrice principale' to specify the female lead.
La recitazione del protagonista mi ha convinto.
The lead actor's performance convinced me.
More analytical phrasing about the acting quality.
Non conoscevo questo attore — è davvero bravo.
I didn't know this actor — he's really good.
Discovery reaction — common with international or debut actors.
Italian cinema awards ('David di Donatello', equivalent to the Oscars) generate lively public debate in Italy. Italians follow domestic film awards closely and have strong opinions about who deserves recognition.