Liverpool's Croatian defender Dejan Lovren confirmed on Friday he has signed a new long-term contract until 2021.
The 27-year-old moved from Southampton in 2014 on a deal worth £20 million and has made 105 appearances since.
"This is one special day for me and my family," said Lovren.
"I think I am the happiest guy (in the world) today, it's another dream come true. It was always my dream to stay as long as possible at one club that I love - and that is Liverpool."
Lovren has endured some difficult times since his arrival at Anfield but his improvement this season he puts that down to manager Jurgen Klopp.
"When Jurgen came in, he changed me a lot. Not just me, he changed a lot of players with the mentality, working hard on the pitch, on the training ground and he is still fresh here because it's only a year and half, but everyone has seen the big difference," he told liverpoolfc.com.
A draw in Thursday's Manchester derby means Liverpool retain third place, one point ahead of City and two ahead of United, with both clubs having a match in hand.
However, with four matches remaining Lovren is confident they can achieve their aim of securing Champions League football.
"I would be stupid if I was to say we don't believe in this," he stated.
"We started the season so strong and we believed from day one in pre-season - and we are still believing.
"Unfortunately, we had some injuries and we were unlucky in those moments, but we still have a big squad with young talents.
"We will definitely fight in the last four games to take all 12 points."
Klopp said Lovren was key to their future progress.
"Dejan is a big presence for us on the pitch and in the dressing room - this is wonderful news that he has committed to LFC for such a long time," he said.
"It is our intention to build this squad around the great talent we already have.
"He is an outstanding defender and someone who, I believe, still has his best times to come as a player."