Spacey, 63, denies three counts of indecent assault, seven counts of sexual assault, and one count of causing a person to engage in sexual activity without consent.
He also pleaded not guilty to a further charge of causing a person to engage in penetrative sexual activity without consent.
The alleged offenses, against four men who cannot be identified under English law, are said to have occurred between 2001 and 2013.
"Kevin Spacey Fowler is an actor; many of you will already know that," lprose cution awyer Christine Agnew told a jury at Southwark Crown Court, using the star's full name.
"He is an extremely famous actor who has won a number of awards. He is also, the prosecution allege, a man who sexually assaults other men."
Agnew said Spacey, a two-time Academy Award winner for "American Beauty" and "The Usual Suspects," did not respect personal boundaries or space.
He was "a man who it would seem delights in making others feel powerless and uncomfortable, a sexual bully," the lawyer alleged in her opening speech.
"His preferred method of assault is it appears to grab aggressively other men in the crotch. On one occasion things went further than that."
Agnew said Spacey had dismissed some of the allegations as "quite simply made up", and others that they were consensual.
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