Guiu moves to the Premier League new-boys on a season-long loan.
Advertisement
Advertisement
Sunderland sporting director Kristjaan Speakman said: "In a loan acquisition, we not only have to convince the player but also the parent club, and we thank Chelsea for placing their trust in us.
"Most importantly, Marc wanted to come to Sunderland and be a part of our club. The competition for his signature was significant and he had many high-quality options.
"Marc's a progressive striker who has key attributes that align with the role in our team."