The Belgian midfielder had been tipped for a £60m move to French champions Paris Saint-Germain this summer after a storming season with Chelsea that saw him register 14 goals and seven assists in 35 Premier League outings.
But the 23-year-old, who has been handed the number 10 shirt for next season, insists he wants to stay at Chelsea and that Chelsea have put an improved contract offer on the table.
He said: “I am staying at Chelsea 100 per cent.
“Of course in football you never know but I am under contract at Chelsea and I want to stay there. And I am in discussions with Chelsea for a new contract.
“It is only the beginning of the talks right now so we have time, but the fact that Chelsea have offered me a new deal means they have a lot of confidence in me that I can do a good job and they can count on me.
“PSG never made any suggestions to me personally.”