* Vonn to have knee surgery
* Will return next season
Olympic downhill champion Lindsey Vonn, one of the biggest attractions in winter sport, will miss next month's Sochi Games because she requires surgery on her injured knee.
The 29-year-old American broke the news on her Facebook page on Tuesday.
"I am devastated to announce I will not be able to compete in Sochi," said Vonn, the girlfriend of world number one golfer Tiger Woods.
"I did everything I possibly could to somehow get strong enough to overcome having no ACL (anterior cruciate ligament) but the reality has sunk in that my knee is just too unstable to compete at this level."
Vonn, a four-times overall World Cup champion and the standout name in women's Alpine skiing, badly injured her right knee in a world championship super-G in February.
She hurt her knee again while training for the season-opening World Cup downhill at Beaver Creek, Colorado but appeared to be back on track after racing at Lake Louise, Alberta.
Vonn then travelled with the U.S. team to Europe and, with Woods watching her for the first time at a World Cup race, injured her knee once more in Val d'Isere, France.
"It was Tiger's first time at a World Cup race and I was really hoping to win my 60th as a present for him," said Vonn who with 59 victories in the competition is three short of the women's record held by Austrian Annemarie Moser-Proell.
Vonn still believed she could recover in time for Sochi, aiming to compete at her fourth straight Olympics, but faced the grim reality on Tuesday.
"After the incident in Val d'Isere an MRI showed an MCL (medial collateral ligament) sprain which, coupled with the torn ACL, has made it impossible to stabilise her knee and be ready to safely ski again next month," Vonn's public relations team said in a statement.
"She will have surgery shortly and is expected to make a full recovery in time for the 2014-15 World Cup season and the 2015 world championship."
Vonn tried to put an optimistic spin on her personal disappointment.
"On a positive note this means there will be an additional spot so that one of my team mates can go for gold," she said in a statement released by the U.S. skiing team.
"Thank you all so much for all of the love and support. I will be cheering for all of the Olympians and especially team USA."
Bill Marolt, president of the U.S. Ski and Snowboard Association, said he expected Vonn to be back at full strength next season and that it was time for her compatriots to step up in Sochi in her absence.
"I have every ounce of confidence that Lindsey will be at the starting gate at the next World Cup season ready to compete. She knows the hard work it takes to get to the top and still has significant goals to achieve in what has been an incredible career," said Marolt.
"While Lindsey won't be in Sochi we have a strong team that is well prepared to challenge. Now is the time for those athletes to step up."
Vonn is a six-times World Cup downhill champion, a four-times World Cup super-G winner and a triple World Cup super combined champion.
She landed the downhill gold medal at the Vancouver Olympics four years ago and also picked up the bronze in the super-G at the same event.