Ousmane Dembélé has joined Borussia Dortmund on a five-year deal, the club have announced.
Looking to bridge the gap between them and once again champions Bayern Munich, Tuchel has picked out Dembélé as a player who can improve an already attacking team, with him bringing both potential and talent to Germany at just 18-years-old.
Both clubs have agreed to remain silent in regards to the details of the transfer, Dortmund confirmed in the announcement of the signing on their official website.
After a spectacular first season with Rennes' first team this year, in which he scored 12 goals in 24 games from an attacking midfield role, Dembélé has been one of the most prominent names in the gossip columns in recent weeks.
Liverpool have been heavily-linked with the £30 million rated teenager, but Jürgen Klopp's old side have pipped him to the transfer.
Dembélé, who has been capped 18 times at youth level for France, will instead turn out in the yellow of Dortmund next season, and the club's Sporting Director, Michael Zorc, is delighted.
"Ousmane can play almost every position on the offensive," he told the club's official website, with Dembélé having featured in as many as eight different roles for Rennes this season.
The teenager can play out wide - either as an out-and-out winger or as a wide attacking midfielder - or through the centre - either as a forward or in a number 10 role. In all roles through, "he is strong in the one-against-one, two-footed, tricky, fast and goal-dangerous," Zorc added, clearly excited about the talent he possesses.
It is reasons such as these that Dembélé was named as Ligue 1's Best Young Player for the season, and he will now look to replicate these performances in Germany's top flight.
Dortmund's persistence persuades
Speaking for the first time as a Dortmund player, Dembélé revealed that one big factor in his decision to join the club was the persistence with which they pursued him.
He said that the club "endeavoured very early" to persuade him to join their project, something which "impressed" the youngster.
The 18-year-old added that the "concept" of the club "convinced [him] totally," and that he "can't wait" to play in front of over 80,000 fans, as well as in the UEFA Champions League.