Actor Kevin Spacey has told a jury touching his accuser was "in my mind romantic", as he gave his defence during his trial for sexual assault.

Appearing at London's Southwark Crown Court, the two-time Oscar winning actor said he had developed a "flirtatious" relationship with an accuser.

He told the jury he and the complainant had been "somewhat intimate", but denied assaulting him.

The 63-year-old faces 12 sexual offence charges, all of which he denies.

The court heard the complainant alleges the incident happened as he drove Spacey to a showbiz party in the early 2000s.

When asked if he caused the accuser to "come off the road" when he grabbed the man, the actor replied: "That never happened. I was not on a suicide mission on any of those years."

Giving evidence, Mr Spacey told the court he had developed a "flirtatious" relationship over time with the accuser, and that he touched the man in "romantic" and "intimate" ways.

"Yeah, I am a big flirt," he told the court.

Speaking about touching the man, he continued: "It did not happen in a violent, aggressive, painful way.

"It was gentle… and it was, in my mind, romantic."

Mr Spacey said the complainant said things like "this is new for me".

He explained the touching did not progress because the alleged victim "made it clear that he did not want to go any further".

Asked by his barrister Patrick Gibbs KC for his reaction to the allegations by the complainant, he said: "I was crushed. I never thought the (name of man) I knew over 20 years later would stab me in the back."

'Never happened'

Addressing accusations by another complainant who alleged Mr Spacey had grabbed his crotch "like a cobra" after using a "vile comment", the actor said he had never done that to anyone in his life.

Mr Spacey told the jury that allegations made by the man - that he allegedly met at a theatre in the mid-2000s - were "madness" because "it never happened".

"I never said any of the things that he claims I said to him and wouldn't and never have to anyone in my life," he told the court.

Speaking of allegations from another complainant, Mr Spacey said he did not recognise the accuser by name or appearance and his records showed he was not in the UK in August 2008, when the man claims the incident took place.

Mr Spacey said watching a video of the complainant who mentioned he was on a bus had sparked a memory of a sexual encounter he had with someone in his flat.

The actor said that when he returned from the bathroom "it was like everything had changed", adding: "The person I had had this intimate moment with was suddenly awkward and fumbling."

Asked whether he met the individual again, Mr Spacey said he did not have a strong memory of it "but my instinct tells me that we may have seen each other again".

"I believe I performed [a sex act] on him," Mr Spacey told the court.

After breaking for lunch, the court heard Mr Spacey's defence against accusations from another complainant who claims he came into contact with the actor while he was working in a pub.

Mr Spacey said on the evening in question everyone was drinking and "pretty much everyone" smoked cannabis.

The actor said he remembered some of the details after seeing the complainant's interview video, but did not have a clear memory about conversations which took place.

Discussing the alleged incident, Mr Spacey said he "made a pass and I am only happy that he testified that the moment he told me he wasn't interested, I stopped".

He told the court he did not remember going back to the pub where the complainant worked the next day, but accepted he did based on witness testimony and said it was probably to apologise.

'I lost everything'

Asked what happened when the first accusations were made against him, Mr Spacey said: "My world exploded.

"I lost my job, I lost my reputation, I lost everything in a matter of days."

Speaking about his decision to come out as gay, Mr Spacey said he had been pressured to do so, and members of the LGBT community were "upset" that he came out while responding to an allegation.

"It wasn't that this story suddenly made me want to come out... I thought in the face of this terrible accusation [I could do something positive]."

The prosecution finished their evidence against the Hollywood star on Wednesday after the jury heard accounts from his four alleged victims.

During their evidence, they variously described him as a "vile sexual predator", "slippery" and "atrocious, despicable, disgusting".

Jurors heard of alleged "aggressive" crotch grabs against three men, while a fourth complainant accused Mr Spacey of having drugged him and performing a sex act on him while he was asleep.

On Wednesday, prosecutor Shauna Ritchie said Mr Spacey told police he was "baffled" by the claims by one man and did not recognise the others.

The actor said he may have made a "clumsy pass" at his final alleged victim but denied deliberately attacking him.

Mr Spacey is accused of sex offences against four men between 2001 and 2013.

He pleaded not guilty in January to three counts of indecent assault, three counts of sexual assault and one count of causing a person to engage in sexual activity without consent.

He also denies four further charges of sexual assault and one count of causing a person to engage in penetrative sexual activity without consent.

All four accusers are entitled to lifelong anonymity under the law.

The Hollywood star won an Oscar for Best Actor in 2000 for American Beauty as well as Emmy nominations for his role in House of Cards.

The trial continues.