Jack Nicklaus, who with 18 major titles is widely regarded as one of the greatest players of all time, was runner-up a record 19 times, including seven at The Open.
Shortly after boarding his plane after the tournament, Oosthuizen, who has over 74,000 followers, took to Twitter to congratulate Thomas on his win - and proceeded to serenade his followers by lip-syncing to the hits song 'Rise Up' by American Andra Day.
The clip was retweeted more than 17,000 times and liked over 44,000 times.
It even drew some reaction from fellow golf stars, with two-time PGA Tour winner Kevin Kisner calling it "world class" and Canadian Graham DeLaet Canadian Graeme DeLaet commenting" "Those vocals bud . . . wow!"