The Bodmin-based business has produced just 3,000 bottles for the shelves of the upmarket food and drink emporium.
Camel Valley Vineyard owner Bob Lindo said: "We pride ourselves that, year on year, the vineyard continues to produce top-quality wines. To be recognised by Fortnum & Mason is a huge honour. Working with them provides us the opportunity to supply our sparkling wine to an international audience."
The sparkling wine will be available from July and is made by Sam Lindo - who was named UK Winemaker of the Year 2007 - using a blend of Seyval Blanc, Reichensteiner and Huxelrebe grapes.
Fortnum & Mason wine buyer Tim French said: "The English sparkling wine market is growing and we are seeing more and more wineries successfully competing against the more established international competition. We decided to work with Camel Valley as they stood out as a leader of England's developing sparkling wine industry.
"It is an exciting time for English sparkling wine and we are delighted to champion the finest examples at Fortnum's."
L For the first time in nearly 10 years a still white wine has triumphed over sparkling wines to be named Wine of the Year in the English & Welsh Wine of the Year Competition.
The competition, which took place at Brightwell Vineyard in Oxfordshire on 26-27 June, saw Gloucestershire-based Three Choirs Vineyards Estate Reserve Siegerrebe 2006 win the Gore-Browne Wine of the Year Trophy, along with the Tom Day Trophy for Best Varietal Wine.
Tom Day was involved with Three Choirs Vineyards when it was first set up in the early 1970s.
The awards ceremony for the competition will take place on 22 July at the House of Lords, hosted by UK Vineyards Association president Lord Montagu of Beaulieu.