Beckham, 34, who was on loan at AC Milan from the Los Angeles Galaxy, was injured during the closing minutes of Milan's 1-0 Italian league win over Chievo Verona.
He took a pass at the ball with his left foot and then stepped back visibly in pain as he put all his weight on his right foot.
He flew to Finland today for surgery on the tendon but is out of action for up to eight months..
Beckham said that "I am upset but want to thank everyone for their messages of support," and said he hopes "to make a swift and full recovery."
This would have been Beckham's final World Cup with England and his international career now appears over.
The soccer wunderkind never experienced the kind of success he should have had at the international level.
Who can forget the fiasco in 1998 when Beckham got sent off in the game against Argentina.
Beckham was red carded after he kicked Diego Simeone on the calf after Simeone fouled him.
Simeone later admitted to deliberately attempting to wind Beckham up.
That match finished in a draw and England were put out on penalties.
Beckham was a hate figure for many England supporters and journalists who blamed him for the team's elimination.
He received death threats after the game for several months while British tabloid the Daily Mirror printed a dartboard with a picture of him as the bullseye.
In 2006, Beckham was taken off injured after half-time and England again lost on penalties when the match went to a draw.
Beckham was one of the most popular players ever at Manchester United but he fell foul of legendary boss Alex Ferguson towards the end of his time there.
Speaking in 2007, Fergie said: "He was never a problem until he got married. He used to go into work with the academy coaches at night time, he was a fantastic young lad. Getting married into that entertainment scene was a difficult thing – from that moment, his life was never going to be the same. He is such a big celebrity, football is only a small part."
Beckham left Manchester United in 2003 at the end of the season.
Earlier that year, he had required stitches after Ferguson allegedly threw a boot at him after the FA Cup defeat to Arsenal.