Franco-Dutch carrier Air France-KLM said it is not involved in the negotiations between Virgin Atlantic and Delta Air Lines about a transatlantic joint venture.

Delta and Virgin plan to set up a revenue-sharing deal on flights between Britain and the United States if the U.S. airline buys Singapore Airlines' 49 percent stake in the UK carrier, a source close to Virgin said.

"Air France-KLM is not involved in current negotiations between Delta and Singapore," a spokeswoman for Air France-KLM said on Monday.

(Reporting by Cyril Altmeyer; Editing by Christian Plumb)