The 43-year-old goalkeeper left Juve at the end of the last campaign, where he had been for two decades, either side of a 12-month spell at Paris Saint-Germain in 2018-19.
Parma's U.S. owner Kyle Krause had teased Buffon's return on Wednesday with a tweet which read: "it's a bird it's a plane it's" -- in reference to the ex-Italy international's Superman t-shirt he wore during the club's 1999 Coppa Italia celebrations during his first spell.
Parma tweeted the announcement with a video of a man in a black hooded jumper, walking on to the club's home pitch to dig up an old treasure chest with a Superman t-shirt and Parma jersey, before Buffon revealed himself and said: "I'm back."
Buffon made his professional debut for Parma at the age of 17 in 1995 and kept a clean sheet against AC Milan. He won the Coppa Italia, UEFA Cup and Italian Supercoppa at the club in 1999 before he left to join Juventus for a then-world record fee for a goalkeeper. The £32.1 million fee in 2001 was a record for 16 years until Manchester City paid Benfica £34.7m for Ederson.
At Juve, he won 10 Serie A titles in 19 seasons, as well as the Serie B title in 2006-07 when the club played in the second tier after they were relegated as a result of the Calciopoli match-fixing scandal. He also won the Coppa Italia five times and the Supercoppa on six occasions. Buffon reached the Champions League final three times with Juve, but was on the losing side in each.
Buffon is the most capped Italian man with 176 international appearances and was part of the 2006 World Cup-winning side, a season which saw him finish second in the running for the Ballon d'Or.
He made his Azzurri debut in 1997 and was part of squads for nine major tournaments from 1998 to 2016 and was an unused sub at the 1998 World Cup. Buffon was also captain of the Italy side which lost to Spain in the Euro 2012 final.