The Tottenham midfielder joined a long line of Premier League stars in applauding Sir Alex Ferguson's side as they wrapped up their 20th title with a 3-0 win over Aston Villa
The Welshman has long been linked with a move to Old Trafford, with Spurs unlikely to be able to retain his services if they fail to qualify for the Champions League.
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On Monday he looked on as Sir Alex Ferguson's side sealed yet another league title on the way to a potentially record-breaking season.
"Congrats to Man United on winning the title," Bale congratulated the champions on Twitter.
He was joined by several other past and present Premier League stars taking the opportunity to congratulate the Red Devils.
"Congratulations to every player, manager, coaches, staff and of course the supporters for an incredible year! #Manutd #20th", tweeted former United keeper Edwin van der Sar.
"#M.U.F.C 20th league title! Congrats to the big red family."
Meanwhile, ahead of Sunday's meeting between the two sides at the Emirates Stadium, Arsenal striker Lukas Podolski tweeted: "congratulation to Man United on winning the title [sic]".