noun
much-discussed work; talked-about book/film/etc.
Refers to a creative work (book, movie, drama, etc.) that has become a hot topic or is widely talked about, often due to its content, quality, or controversy.
今年の話題作を全部見た。
I watched all the talked-about films of this year.
彼の新作は大きな話題作になった。
His new work became a much-discussed piece.
ヒット作 emphasizes commercial success (a 'hit'), whereas 話題作 emphasizes being widely discussed, regardless of sales.
Compound of 話題 (topic of conversation) + 作 (work, production).