Jennifer Siebel Newsom — wife of California Gov. Gavin Newsom — sobbed as she described Harvey Weinstein’s “distorted” and “fish-like” genitals during her bombshell testimony at the disgraced movie producer’s sexual assault trial Monday.

Identified in court at Jane Doe 4, Siebel Newsom broke down in tears recounting how Weinstein allegedly raped her in 2005 at the Peninsula Hotel in Beverly Hills.

“I’m standing. Im resisting,” she said. “Horror. I’m trembling. This is my worst nightmare. I’m just this blow-up doll that he’s just trying to masturbate off of.”

When asked by Deputy District Attorney Marlene Martinez to describe Weinstein’s physique, Siebel Newsom said: “Lots of bruises, markings, yellow and green, lots of stretch marks on his belly, very not physically fit at all. Looked uncircumcised and strange though, kind of fish like, the penis, something was distorted in the testicles… Lots of skin, lots of skin down there.”

Siebel Newsom, a former actress, is the fourth woman to take the stand who has accused Weinstein of sexual assault in his trial at Los Angeles Superior Court.

Weinstein — who is already serving a 23-year sentence for rape and sexual assault in New York — is facing cahrges for allegedly sexually assaulting four women in Los Angeles between 2004 and 2013.

Siebel Newsom, 48, said she agreed to meet Weinstein at his hotel suite to discuss a film project, and because “he could make or ruin your career.”

Once they were alone in the room, however, Siebel Newsom said Weinstein changed out of his suit into a robe, then started to “manipulate” and “threatened” her, while mentioning several actresses’ names.

She said Weinstein penetrated her private parts with his fingers and then his “deformed” penis.

Siebel Newsom tearfully said: “He knows this is not normal. he knows this is not consent,” adding at first Weinstein couldn’t get an erection.

“And then he puts part of his penis inside of me because he pushes me back against the bed,” she said. “It’s not staying in because his penis is so weird and messed up. He realizes this. I was just worried I was going to get some disease. it was so gross.”

Siebel Newsom said she was frozen in fear but put her hand on Weinstein’s penis to “try to make him stop.”

“Oh, I just made some noises to get him to ejaculate faster,” Siebel Newsom said. “Just like pleasure noises.”

After Weinstein ejaculated, Siebel Newsom said she was speechless. “I just wanted to get the f— out of there,” she said in tears. “Pardon my language.”

When asked by Martinez why she continued to correspond via email with Weinstein even after the alleged rape, Siebel Newsom said she felt what happened was a “one-off thing” and that Weinstein had gotten married.

“I tried to put what happened into a box, even though it came out at times,” she said. “And my sadness and my fear changed at times into anger.”

Siebel Newsom was also asked about an email she sent to Weinstein in 2007 where she sought his advice when Newsom was mayor of San Francisco. In a prior ruling, Judge Lisa Lench granted prosecutors permission to use the email, which mentioned an affair Newsom had in 2005 with an aide.

“I believed that Harvey Weinstein had relationships with the press and understood how to handle the press, and thought he could be helpful,” Siebel Newsom said when asked about the email on Monday.

During a 15-minute cross-examination, defense attorney Mark Werksman hammered Siebel Newsom about a $500 campaign contribution Weinstein made to her husband’s campaign.

Siebel Newsom said her husband’s staff had asked for the donation under her suggestion but said the money was returned after the MeToo movement.

“When did you tell Gavin Newsom about his allegation of sexual assault,” Werksman asked.

“I told him that Harvey was sketchy at different times, and he picked up on it himself when he met him,” she replied.

During his opening statement, Werksman made a dig at Siebel Newsom, saying: “Today she is the wife of Gov. Newsom. She’s the first partner of California … She’s made herself a prominent victim in the MeToo movement … otherwise she’d be just another bimbo who slept with Harvey Weinstein to get ahead in Hollywood.”

Siebel Newsom will continue her testimony on Tuesday.