By Patricia Towle and John South

Desperate Housewives star Eva Longoria was knocked unconscious and rushed to an L.A. hospital during the filming of a prison scene for an upcoming episode of the hit ABC series, The National Enquirer has learned exclusively.

The petite, dark-haired actress was on location at City College in Pasadena, California filming a reunion scene with her imprisoned husband &#151 played by actor Ricardo Antonia Chavira &#151 when the accident occurred at about noon on Wednesday August 17.

Longoria, 30, who plays housewife Gabrielle Solis on the show, is said to have regained consciousness before being rushed from the set by paramedics to a nearby hospital.

“Eva and another male actor dressed in suit and a tie, were walking by a group of prisoners behind a chain link fence,” said an eyewitness. “The prisoners began cat-calling and jeering at Eva. “One of them then grabbed the tie of the man and yanked him over against the fence.

“When that happened, a steel bar supporting the fence broke loose and flew out, striking Eva in the head.”

The impact was severe enough to knock her out. “She was unconscious nearly four minutes.

“One of the crew picked her up after she regained consciousness and she was rushed off to a nearby hospital.”

The National Enquirer confirmed that Longoria was treated and released from the hospital and is now at home resting comfortably.

According to a spokesperson for Desperate Housewives, “Eva luckily was only slightly injured.”