Jessica Simpson furious over Eva Longoria's friendship with John Mayer

Jessica Simpson flew into a rage when she learned pal Eva Longoria was hanging out with her ex-boyfriend, it has been claimed.

Sources say Dukes of Hazzard beauty Simpson was furious when Desperate Housewives actress Longoria spent time at a New York bar with musician John Mayer.

A source said: "When Jessica heard that Eva was being friendly and polite to John, she called her a back-stabber and was furious. "She went nuts."

A spokesperson for Simpson, now dating American football star Tony Romo, said: "There's no truth to Jessica being upset with Eva Longoria. They are great friends."

Mayer, 30, and Simpson, 27, dated for several months following her split from ex-husband Nick Lachey.

Longoria, 32, wed basketball star Tony Parker, 25, in July.