The Burkina Faso international agreed a four-and-a-half year contract with the Premier League club back in October after impressing while on trial during their pre-season tour of Asia.
Traore, who made his international debut at the age of 15, has now officially made the switch to Stamford Bridge from Association Jeunes Espoirs De Bobo-Dioulasso.
And the 18-year-old - who played a part in all three of Chelsea's games in Asia, scoring in Malaysia and Indonesia - has reflected on his time with Jose Mourinho's first team, adding that he is thrilled to be joining the club while also hailing the Portuguese.
"I was very happy," Traore told Chelsea's official website when asked about how he found the pre-season tour.
"It was a good experience with all the senior players and I learned a lot from them. I was very proud so it was a dream for me to be there every day and playing games.
"On the pitch I was comfortable, I wasn't nervous once I was on the pitch. Jose Mourinho spoke a lot during training and he is one of the best managers, maybe the best in the world.
"He is a very good person and it is a dream for me to work with him. I can now say I am living a dream."
