Emmerdale actor Mark Jordon growled "like a mad dog" before biting a pensioner and spitting out a chunk of his skin, a court has heard.
The 54-year-old, who plays Daz Spencer in the ITV soap, is said to have attacked Andrew Potts after he allegedly called Jordon's daughter a "s**g".
Jordon is also accused of screaming "I'll f****** kill you" after a row broke out in a beer garden in Oldham, Greater Manchester, on 1 July last year.
The former Heartbeat actor later pushed over Mr Potts' girlfriend Rosalind O'Neill before biting the pensioner's thumb and spitting out his flesh, the court heard.
Jordon is then said to have bitten Mr Pott's eyebrow after they both fell to the ground.
The pensioner wiped away tears as he described the "frightening" incident at Manchester's Minshull Street Crown Court.
Jordon's Emmerdale co-stars Chris Chittell, Nick Miles and Sammy Winward sat in the front row of the public gallery for the hearing.
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The row out broke out when Miss O'Neill made the comment "I hope they are using protection" after Jordon's daughter was seen "straddling" a boy in the beer garden of the Farrars Arms, the court heard.
Mr Potts told the jury: "The next thing I see is Jordon on the other side of our bench screaming at Rosalind, I mean really screaming.
"He said, 'That's my f****** daughter you are talking about."
Miss O'Neill apologised but Mr Potts remarked that he "wouldn't let my daughter act like that in front of me", the jury was told.
CCTV footage showed Jordon having to be held back from attacking the pensioner.
Mr Potts said the soap star was "like a madman" and was dragged back as he screamed: "I'll f****** kill you, you old bastard."
He told the jury he threw a couple of punches at Jordon and the actor's nose started to bleed.
Mr Potts added that he did not strike Jordon on the nose and believed the actor had taken cocaine.
Keith Harrison, defending, suggested Mr Potts had called Jordon's daughter a "s**g".
Mr Potts said: "No, 100%, not at all."
He also denied saying he had filmed the girl and would post it on YouTube.
Mr Potts told the court he might have said "f*** off, you think you're clever because you're on TV" to Jordon's girlfriend Laura Norton, 36, who plays Kerry Wyatt in Emmerdale.
Asked if he had called Jordon a "d*******", Mr Potts laughed and said: "He was acting like one."
Mr Potts and Miss O'Neill were escorted from the pub, the court heard.