The Argentine wizard becomes PSG's fourth free-transfer signing for the summer following the arrivals of former Liverpool midfielder Georginio Wijnaldum, Spain defender Sergio Ramos and Italy goalkeeper Gianluigi Donnarumma.
Rejecting the number 10 shirt which was offered to him by his former teammate Neymar, Messi will don the number 30 shirt, his first shirt number at Barcelona.
In a reunion with Neymar, PSG will be a delight to watch as they gear up for a Champions League title for the first time.
Messi after signing his new deal insists he's ready to help the side accomplish their objectives.
"I am excited to begin a new chapter of my career at Paris Saint-Germain. Everything about the club matches my football ambitions.
"I know how talented the squad and the coaching staff are here. I am determined to help build something special for the club and the fans, and I am looking forward to stepping out onto the pitch at the Parc des Princes," Messi said in a statement.
PSG club president Nasser Al-Khelaifi also added;
"I am delighted that Lionel Messi has chosen to join Paris Saint-Germain and we are proud to welcome him and his family to Paris.
"He has made no secret of his desire to continue competing at the very highest level and winning trophies, and naturally our ambition as a club is to do the same.
"The addition of Leo to our world class squad continues a very strategic and successful transfer window for the club. Led by our outstanding coach and his staff, I look forward to the team making history together for our fans all around the world."
Having brought to an end of a 21-year stay at Barcelona, Messi remains the club's record scorer with 672 goals and won 10 La Liga titles, four Champions Leagues, seven Copa del Rey trophies, including six Ballon d'Or glories.
