The 27-year-old has struggled to earn regular game time under Xavi.
Bellerin only signed a one-year deal with Barca, played just seven matches for the Catalan giants in all tournaments.
The Spain international joins Ruben Amorim’s side as a replacement for Pedro Porro, who joins Tottenham Hotspur on a five-and-a-half year deal.
Following the exit of Bellerin, the Blaugrana are understood to be on the verge of strengthening their defence with the signing of LA Galaxy defender Julian Araujo.
⚪🟢 𝙑𝙀𝙍𝘿𝙀 𝙀 𝘽𝙍𝘼𝙉𝘾𝙊 são as tuas cores 🟢⚪
— Sporting Clube de Portugal (@Sporting_CP) January 31, 2023