Genoa striker Krzysztof Piatek has joined Serie A rivals AC Milan for about 35m euros (£30m).
The Poland international, 23, will replace Gonzalo Higuain, who has joined Chelsea from parent club Juventus.
Piatek, who has signed a deal until 2023, scored 19 goals in 21 games after joining Genoa from Cracovia in July.
He became the first Serie A player since 1949-50 to score eight goals in his first six top-flight games and is fourth in the scoring charts on 13.
Milan are fourth in Serie A, six points behind city rivals Inter Milan in third and 22 points behind leaders Juventus.
Find all the latest football transfers on our dedicated page.