#ZoëKravitz is showing off her new bling from fiancé #HarryStyles! Her engagement ring was on full display at Jessica McCormack's cocktail event in London on Wednesday. Diamond enthusiasts believe it could cost up to $600,000 and boast a large 10-carat diamond. | 📷: Max Cisotti/Dave Benett/Getty; Darren Gerrish/WireImage