Goal reported earlier Monday that the attacker was on the verge of a shock move from the Serie A side , who he joined this past summer, to link up with the Liga champions.
The transfer includes a €8 million (£7m/$9m) option to buy, while Barca will pay a €2m loan fee for Boateng to feature for them the remainder of the season.
The 31-year-old will be presented on late on Tuesday morning, with a private contract signing set to be followed with a photo session on the Camp Nou pitch and a press conference at noon UK Time.
A statement on the club's official website reads: "Kevin-Prince Boateng is a player who will surely adapt quickly to the team. With experience of playing in four of the biggest leagues in Europe, the Premier League, the Bundesliga, Serie A and La Liga, he is a man who has scored goals wherever he has been.
"Furthermore, Boateng is a player who versatile to a fault. During his time with Las Palmas with Quique Setién as coach he played as an out and out striker, a typical number ‘9’. However, he is also able to play further back as he did at AC Milan, scoring twice against Barça in his time with the Rossoneri.
"His ability to bring people into the game means he is excellent at playing behind the main striker."
Before the Blaugrana's confirmation, Boateng himself had announced the deal in an interview with Sky Sports .
"Barca, I’m coming!" he said. " I’m sad to leave Sassuolo but this is a great chance."
The attacker also downplayed previous comments made about Barca's rivals Real Madrid.
In a 2017 interview, Boateng answered he preferred Real Madrid to Barcelona, while also stating in the past that he could have made it at the Bernabeu had he applied himself harder earlier in his career.
However, the player says his focus is on his new club, and aiming to find the net against Real Madrid when the two sides next meet in the Spanish capital on March 2.
"Don’t ask me about Real Madrid... is just the past! I only want to focus on Barcelona and I hope to score at Bernabéu for the next Clasico.”
Barcelona will be Boateng's fourth club in the past three seasons, though the former Ghana international has fared well at each of his stops.
He found the back of the net 10 times in 28 La Liga games for Las Palmas in 2016-17, followed by a move to Eintracht Frankfurt in the Bundesliga, where he scored six goals in 31 league matches.
His time at Sassuolo also started well, as in 13 Serie A matches, Boateng scored four goals, though he has not found the back of the net since the end of October.
Boateng will fill in attacking depth for the La Liga champions, as Barca manager Ernesto Valverde admitted the club was looking for options there after allowing Munir El Haddadi to depart earlier in the window .
He becomes the second addition during the winter window, with Barca having also signed Valencia defender Jeison Murillo in January.