Call him Sir Andy Murray now ... 'cause the tennis superstar was at Buckingham Palace on Thursday -- receiving his knighthood from Prince Charles himself!!
The 32-year-old actually learned he'd be receiving the honor back in 2016 ... but he held off on having the ceremony until this week because of his tennis schedule.
Tennis superstar Sir @andy_murray has received his #knighthood from Prince Charles at Buckingham Palace. ud83cudf96ufe0f
The three-time Grand Slam champion said he wishes his daughters could have seen him receive the award.