Manchester United midfielder Marouane Fellaini has officially committed his future to the club by signing a two-year contract until the summer of 2020, with the option of a further 12 months that will extend the deal to 2021.

It means that Fellaini, who was due to be out of contract this summer, could see his Old Trafford stay reach as many as eight seasons in total if the extension is triggered.

"I am pleased to be continuing my journey as a Manchester United player. I made this decision because I am very happy here. Also, I feel like this team, under Jose, still has a lot we want to achieve," Fellaini told

"I would like to say a special thank you to Jose for the faith he has always shown in me. My focus now is on the World Cup and I am looking forward to a successful season ahead."

Manager Jose Mourinho was keen to have Fellaini continue as a United player.

"I am very happy Marouane is staying with us," he said. "I always believed in his desire to stay with the club and I am delighted that he has signed a new contract."

Fellaini initially joined United for £27m from Everton in the summer of 2013. He has played over 150 games for the club and has won the FA Cup, EFL Cup and Europa League during that time.