Credit: Jason Merritt/Getty Images

Thank goodness for that five-second delay!

Melissa Leo dropped the F-bomb during her emotional, off-the-cuff acceptance speech for Best Supporting Actress at Sunday's Oscars.

"Yeah, I am kind of speechless," the actress, 50, said at the podium after thanking her family and her colleagues working on The Fighter.

Referencing Oscar winner Kate Winslet, she said, "When I watched Kate two years ago, it looked so f***ing easy."

(During the telecast, her cuss-word was already bleeped out.) Leo instantly covered her mouth following the gaffe as the crowd laughed.

She pulled herself together and rounded up her thank-you speech -- even flirting with presenter Kirk Douglas, 94. "You're much more beautiful than you were in the Fighter," Douglas joked.

Her reply: "You're pretty good looking yourself. What are you doing later on?"

Oscar co-host Anne Hathaway was tickled by Leo's unscripted blooper.

"Wow, I thought the 'F' stood for 'The Fighter.' It's the young and hip Oscars!"