It’s the most infamous stained dress in presidential history, but Monica Lewinsky says when she wore it after her widely chronicled hookup with President Bill Clinton, no one noticed.

“I went to dinner that night. None of these people said to me, ‘Hey, you’ve got to go to the bathroom, you’ve got stuff all over your dress,’” Lewinsky said in “The Clinton Affair,” a new A&E series.

She said she also didn’t spot the telltale semen stain that proved she and Clinton were more than just friends.

Lewinsky went into detail about the day the piece of evidence was created, as she continued to carry on a years-long relationship with Clinton in the early months of 1997, after he won re-election.

Clinton had invited Lewinsky to a White House radio address, she recalled.

“He said he had a present for me. I didn’t quite know — would I get to see him alone? Wouldn’t I?” Lewinsky said.

“As I went through to shake his hand after and take a picture with him, he said, ‘Oh, go see Betty, she has something for you.’”

The president was referring to Betty Currie, his personal secretary, whose desk was right outside the Oval Office.

“She brought me into the Oval Office and all three of us went into the back study, and she went into the dining room to hide there,” Lewinsky added.

“Because the illusion to everyone else was that I was not alone with him.”

The president gave Lewinsky a box with a hat pin, telling her he got it for her because “’you always look so cute in hats,’ or ‘you and your hats,’ or something like that,” Lewinsky said.

He also gave her a “really beautiful copy” of “Leaves of Grass” by Walt Whitman.

“It was a very meaningful present to me. It’s an intimate book that you don’t give lightly. Whatever had been nagging in me — is what I’m feeling real? Is that there? Whatever those insecurities were, they kind of vanished in some way with him giving me this gift,” Lewinsky said.

She explained that this was the first time she and the president had been together since she had been “banished” to the Pentagon, a decision she believed was made to keep her from affecting the 1996 presidential election.

“And so we moved to the bathroom and were more intimate. There was some attention paid on me and then I was reciprocating, where up until that point he had always stopped before completion on his part,” Lewinsky said, delicately trying to explain their encounter.

“I sort of stood up and said I wanted to move past that stage and so he finally said OK.”

That’s when the dress was soiled, but Lewinsky didn’t notice at the time.

“So that finished and then I hugged him after. And he hugged me,” she said. “And off I went.”

In 1998 grand jury testimony, she said she initially thought the marks on her dress “could be spinach dip or something.”

In a prior interview, Lewinsky said she didn’t notice the stain until she took the dress out for Thanksgiving. She tried it on for confidante Linda Tripp, who told her it made her look fat.

When the two women figured out that the president’s semen was deposited on the blue Gap dress, Tripp — who was taping Lewinsky — encouraged her to keep it.

“The Clinton Affair,” a six-part series produced by Alex Gibney and directed by Blair Foster, begins airing on A&E on Sunday, Nov. 18.