Weston McKennie has completed an initial loan move to Juventus, though Schalke could eventually receive €30 million ($48m AUD) from the deal.
Juventus have completed the signing of Weston McKennie, who arrives on loan from Schalke with an obligation to buy should certain criteria be met.
United States international McKennie, 22, was deemed a surprise target for Juve given he was being linked with more modest-level Premier League clubs.
But the Serie A champions had been in the market for midfield reinforcements following Blaise Matuidi's exit to MLS side Inter Miami.
Juve confirmed they have paid €4.5 million for the loan and will be obliged to sign the player permanently for an initial €18.5m – potentially rising by a further €7m – upon the "achievement of certain given sporting objectives by the end of the 2020-21 season".
Even if that clause is not triggered, Juve will still have the option to purchase McKennie for the same price if they please.
Schalke's head of sport, Jochen Schneider, acknowledged that losing a promising young player is not ideal for the club but the situation had been forced upon them by financial problems.
He said: "The agreement we have made with Juventus is the most financially beneficial for Schalke and the most attractive sporting move for Weston.
"Obviously deciding to let go one of our most talented players like Weston is partly down to the financial state the club is in.
"We would like to thank Weston for his outstanding performances and wish him all the best for his time at Juventus."
McKennie joined Schalke in 2016 and went on to make 91 appearances for the club across all competitions after breaking into the first team in 2017-18.
A versatile player capable of playing in defence or midfield, though predominantly the latter, McKennie is Juve's second signing ahead of the 2020-21 season after Arthur arrived from Barcelona.