The 22-year-old, who has scored 26 goals in 55 international appearances, having made her South Korea debut aged just 15, has joined the Blues from Japanese league and cup holders INAC Kobe Leonessa.

"She is one of the best midfielders in the world and our fans will love her," said Chelsea manager Emma Hayes as the London club announced Ji's signing on Monday.

"She has got everything and is a great fit for our team, and I've no doubt she will prove a big success in a Chelsea shirt."

In a Chelsea statement, Ji, a three-time Korean Footballer of the Year, added: "I am glad to be joining Chelsea Ladies and look forward to the new challenge of playing football in Europe.

"I will get myself in gear to become an integral player for my team and to lead Chelsea to the highest possible levels."

Ji is Chelsea's fifth pre-season signing, with the Blues having already added the England quartet of Rachel Williams, Laura Bassett, Gilly Flaherty and Katie Chapman to their squad for this year's WSL, which starts in April.