Chelsea has signed Pedro Neto from Wolverhampton on a seven-year contract for a reported transfer fee of 54 million pounds ($69 million).
The Portugal international joins Enzo Maresca's team ahead of Chelsea's Premier League opener against Manchester City next weekend.
Neto spent five seasons at Molineux, scoring two goals and providing nine assists in 20 appearances last season.
He told Chelsea's official website: I feel really grateful to have joined this club.
I have worked really hard in my career to be here and I'm looking forward to getting on the pitch with this shirt.
The 24-year-old winger was unveiled at Stamford Bridge at halftime of Chelsea's final pre-season match against Inter Milan on Sunday.