Gabuza, 31, has been on the periphery of the Pirates squad this season since his infamous walk-off in a league clash against Black Leopards on August 28.
Having failed to find the net in 14 appearances across all competitions this season, his six-year stay with the Soweto giants was widely speculated to come to an abrupt halt.
And Masandawana has seemingly won the race for his signature, snapping him up on a two-year contract with an option of a third.
The 12-time capped Bafana Bafana attacker has scored 21 goals and registered 11 assists in 157 league games since making his professional debut for Golden Arrows in 2009.
Breaking! Orlando Pirates striker Thamsanqa Gabuza has agreed to join #AbsaPrem champions Mamelodi Sundowns on a pre-contract agreement upon the expiry of his contract at the end of the season. pic.twitter.com/IztasWC9pD— Kick Off (@KickOffMagazine) April 1, 2019