Former pro wrestler Hulk Hogan said Monday he was "completely humiliated" by the publication of a video showing him having sex with his then-best friend's wife.

Testifying in his privacy lawsuit against the Gawker website, Hogan said he didn't authorize the tape to be made or authorize Gawker to publish it. Hogan said when he realized that his best friend, radio personality Bubba the Love Sponge Clem, was involved in making the tape, he began shaking uncontrollably. He added that he felt "badgered" by the Clems into having sex with Heather Clem.

Earlier, Hogan testified that he initially thought it was a joke when Clem said his wife wanted to have sex with Hogan. He testified that the Clems had an open marriage.

Hogan is suing Gawker for $100 million US for publishing the sex video.

The trial finished for the day around 4:30 p.m., when Gawker's attorneys were cross-examining Hogan.

An attorney for Gawker questioned Hogan about inconsistencies in his testimony and media interviews. Hogan testified that he didn't watch the video when he discovered its existence; during a media interview he said he did. And Hogan said he didn't know he was being videoed when he had sex with Heather Clem. But in media interviews in 2012, Hogan said he asked Bubba Clem if he was being filmed.

Hogan, whose real name is Terry Bollea, chalked up the inconsistencies to being shell-shocked by the tape and because he routinely put himself in his wrestling character.

"I was probably in the Hulk Hogan mode," Hogan said. "It gives you artistic ability, to be a character."

Both sides in Hogan's privacy lawsuit have portrayed him as a hero to little kids, a well-known entertainment figure and an American icon.

The civil trial, which started Monday in downtown St. Petersburg, pits the rowdy wrestling star against a maverick news-gossip website known for pulling no punches with celebrities and other famous figures.

Both sides agree that in 2006, following a messy divorce, Hogan had sex with Heather Clem. Hogan's lawyers said there were three sexual encounters; at least one of them was captured on video.

It's unclear who leaked the video to Gawker and other media, but some police reports claim it was a disgruntled producer on Bubba Clem's radio show.

An attorney for Hogan told jurors that Gawker "crossed the line" when posting the video, portraying Gawker founder Nick Denton and his reporter as reckless and profit-hungry.

"They knew what they were doing, but they didn't care."

Denton, meanwhile, has said the case involves important First Amendment questions.

Hogan is seeking $100 million in damages for emotional distress and invasion of privacy. Jurors may be asked to consider how celebrity affects privacy.

Hogan testified Monday that it's "part of the deal, you've lost your anonymity when you become Hulk Hogan."

Gawker says the publication was a legitimate scoop because Hogan had talked openly about his sex life before, in forums such as Howard Stern's radio show.

The lawyer for the New York-based website says Gawker has a right to address uncomfortable subjects, reject spin by celebrities and tell the truth.

Gawker attorney Michael Berry told jurors that the media company doesn't know who sent the video.

He acknowledged that Gawker broadcast one minute and 41 seconds of the 30-minute video in 2012 and that around nine seconds of the edited video included sexual content. Gawker's reporter, A.J. Daulerio, posted the video to accompany a story about how celebrity sex tapes fascinate the public — while being lacklustre.

"Celebrity sex is incredibly dull," said Berry.

Berry said Gawker didn't make money off the post. Advertisers don't post ads on Gawker's items that are labeled "NSFW," or "not safe for work."

He also said news of the tape, including screen shots, was on other gossip sites before Gawker published the video.

Berry added that Gawker founder Denton "wants people to know the truth. The simple unvarnished truth."

The trial is expected to last three weeks.

Hogan attained pro wrestling stardom in the 1980s and 1990s, winning multiple championships. He also became a celebrity outside his "Hulkamania" fan base, appearing in numerous movies and television shows, including a reality show about his life on VH1, Hogan Knows Best.