The player had been widely tipped to leave the Brazilian club for Tottenham upon the completion of the Confederations Cup and it has now been announced he will be on his way.
Paulinho revealed that he had also been a target for Inter Milan but he was happy to be making the move to Spurs.
"The other interest we got was of Inter Milan, but the only offer came from Tottenham," he told a press conference.
"The proposal came, we sat down, analysed it and decided. It was a big decision to go to a big club. There comes a certain point when you need new challenges."
He also used the occasion to thank Corinthians fans for their support, adding: "It's hard to say anything at a moment like this, but I am sure those were three wonderful years in my career, with many titles.
"What I have to say to Corinthians fans, board and staff is 'see you soon' - I will be back in no time, due to everything they have done for me.
"My individual titles are all thanks to the club, Corinthians will be in my heart for the rest of my life."
Corinthians director of football Roberto de Andrade reciprocated those warm remarks about the popular 24-year-old.
He said: "I want to thank Paulinho for everything he has done for Corinthians.
"We will never forget him - the great person he is - and his national team title (the Confederations Cup with Brazil) is well-deserved.
"Corinthians are proud for having had a player like him. It's fair he continues his life at an English club, to know a new culture."
There had been speculation that Paulinho could be involved in the Recopa Sudamericana (equivalent of the UEFA Super Cup) games against Sao Paulo, the first leg being on Wednesday.
But Paulinho has confirmed that although he would relish the chance to sign off with another trophy, he must now focus on Tottenham.
"I will not play in the Recopa because there are contractual requirements of Tottenham which cannot be discussed here," he added.
"It was a decision that we all respect. Of course, I had a huge desire to win another title but the transfer has to be completed."