Javier Mascherano has described his move from Liverpool to Barcelona as "the opportunity of a lifetime".
The Argentina midfielder signed a four-year deal with Barca last night after successfully undergoing a five-hour medical.
He was unveiled to the fans at the Nou Camp and then spoke to the press, and could not hide his delight at joining Pep Guardiola's hugely successful side.
He said: "I know that they've won everything, it's a team full of great players, with a base of world champions and I will try to be humble and help the team continue winning things.
"I'm going to have the chance to play with players who I admire and I will be able to say that I've grown and that I've been a better player at this club. This is an opportunity of a lifetime. I will train to be ready when I'm needed."
Mascherano knows he has a fight on his hands to get in Barca's starting line-up though, with Guardiola having eight of Spain's World Cup-winning squad to choose from as well as the likes of Lionel Messi, Dani Alves and Seydou Keita.
"It would be stupid if I thought I was going to play all the time," he added.
"You need to respect the people here who have been doing so well.
"In my position there are three world champions who have won everything (Xavi, Sergio Busquets and Andres Iniesta). "For me it is a dream to grow, learn and enjoy playing next to them."
Mascherano also insisted he is not a like-for-like replacement for fellow midfielder Yaya Toure, who recently left Barca for Manchester City in a big-money move.
"Toure is a great player, he has left his mark on this club," said Mascherano, who will wear the number 14 shirt vacated by Thierry Henry this summer.
"I've not come to replace him, but to do my job the best that I can.
"They've signed me for what I've done in the last few years. I'm not going to try and be similar to Toure, because I'm not.
"But I can give different things, neither better or worse, but different.
"I'm a defensive player, but I can contribute other things. In my career I've played in other positions and whatever I'm needed to do I'll do it. The coach will decide."
Mascherano is Barca's third signing of the summer following the arrivals of David Villa and Adriano and, according to sporting vice- president Josep Maria Bartomeu, it completes their transfer dealings.
"The squad is now complete and we will not sign anyone else," said Bartomeu, who also revealed Mascherano had taken a significant pay cut to join the Spanish champions.
"We have reached the decision that there is no need to strengthen the team any further."