The Portuguese giants announced the deal on their website late on Sunday evening, with rumours that it was a done deal having emerged on Friday night.
Bosingwa has allegedly been a target for Manchester United, but it's Chelsea who have landed the 25-year-old, who has fast established himself as one of the best full-backs in Europe.
"FC Porto want to inform the market that we have come to an agreement with Chelsea about a transfer of the playing rights of athlete José Bosingwa for the price of €20.5 million," read a statement on the club's official website.
"We further inform that the deal concerning this transfer will be formalized once the player undergoes a medical exam, with the consent of Futebol Clube do Porto."
Chelsea later confirmed on their own official website that, once Portugal's involvement in Euro 2008 has concluded, he will arrive at Stamford Bridge on a three-year deal.
The right-back, also adept in right wing, came through the ranks at Boavista, where he attracted the eye of Jose Mourinho in 2003. The Special One got his man, and he was part of the Champions League winning squad in 2004, and his profile has only risen since.
Bosingwa has earned six caps for Portugal, and is likely to be their first choice right-back at this summer's European Championships, in an uncanny parallel with Blues defender Paulo Ferreira, who was another Portuguese right-back, who arrived from Porto before Euro 2004.
Sulmaan Ahmad, Goal.com