"This game will be my most important - not only with Werder but in my whole life," the Brazilian playmaker told Bremen's official website.

"I am very happy that I have a chance of giving something back for all the devotion that was given to me in Bremen.

"I am top motivated and will give everything I have in Berlin."

Diego will join Italian giants Juventus after spending three years with Bremen.

He put in outstanding displays with the four-time German champions but did not win a major title with them.

"For sure it will be difficult for me to leave Bremen. I will always look back nostalgically on Bremen," Diego added.

"I had three excellent years here, the best of my career and my life. Regardless of what happens, Werder Bremen will always be in my heart."