WILMINGTON, Del. — Hunter Biden’s sister-in-law-turned-lover Hallie Biden testified Thursday that the first son introduced her to crack cocaine in the summer of 2018 and she was “embarrassed” and regretted “that time of my life.”

Hallie, the widow of Hunter’s late brother, Beau Biden, also told a federal court why and how she threw out the .38-caliber revolver prosecutors say Hunter illegally bought and owned — before undergoing a withering cross-examination by defense attorney Abbe Lowell.

Hallie — testifying under the promise of immunity — recalled the pivotal moment she found Hunter’s gun on Oct. 23, 2018.

She said she hadn’t seen the Biden son, now 54, for a while and he had shown up at her home either early that morning or late the previous evening looking worse for wear.

“He was tired, exhausted, looked like he hadn’t slept,” Hallie testified.

When prosecutor Leo Wise asked if Hunter was on drugs at the time, Hallie responded he “could have been.”

Hallie said she went to tidy up Hunter’s Ford Raptor truck “to clean out any drugs or alcohol in the car … in an effort to help him get or stay sober.”

Asked what she found inside, Hallie said: “Aside from trash and clothes, I found remnants of crack cocaine, paraphernalia — oh, and the gun, obviously.” 

“I panicked and I wanted to get rid of them,” she said of the Colt Cobra revolver and ammunition. “I didn’t want him to hurt himself or [for] my kids to find it and hurt themselves.”

“I considered hiding it somewhere but I was afraid one of my children would find it,” she explained. “I was afraid to kind of touch it. I didn’t know if it was loaded.”

Hallie said she fetched a plastic shopping bag and put the gun inside. Realizing the weapon was still recognizable through the bag, she grabbed a brown leather pouch, shoved the firearm inside, drove to the local grocery store and tossed it into the garbage.

The jury was shown the pouch — which had scuff marks and ink stains on it and which Hallie said Hunter had used for either his business cards or drugs.

“I was so flustered from the whole thing,” Hallie said. “I realize it was a stupid idea now, but I was just panicking.” 

The jurors were then shown surveillance footage of Hallie driving up to Janssen’s Market and putting the pouch inside the garbage can. They were then shown another clip of her coming back to the bins roughly 30 minutes later and searching for the gun without success.

Hallie confirmed she did not tell Hunter she was getting rid of the gun, saying: “I was just going to pretend like it wasn’t me.”

But Hunter immediately became suspicious after realizing the gun was gone, asking Hallie in a text message: “Did you take that from me?”

“He was angry with me,” she testified Thursday.

Hallie said when she fessed up to Hunter about what she’d done with the gun, he told her “to go look for it.”

“When I looked for it and didn’t find it, he told me to file a police report for it,” Hallie said. “Because it was registered in his name.”

When Lowell’s turn for questioning came, the defense attorney drilled down on Hallie’s vague memories, noting that the witness did not remember exactly when she saw Hunter on either the night of Oct. 22 or morning of Oct. 23.

“There are just some things you remember and many things you don’t,” Lowell said at one point before asking Hallie where in the Ford she had found the “dusting” of crack cocaine.

“I don’t recall,” Hallie responded.

Lowell inquired what drug paraphernalia she found inside the pickup, to which she repeated: “I don’t recall.”

“On that morning [of Oct. 23], you’re not certain when you went into the car?“ Lowell asked.

“Correct,” Hallie answered.

“You’re not certain when you saw him?“ Lowell pressed.

“Correct,” she answered again.

While prosecutors don’t have to prove that the Biden son was high when he bought the gun, they do need to show that he was using drugs around that time. 

Lowell has argued that Hunter was struggling with alcohol abuse, not drug abuse, at the time prosecutors say he lied about his crack addiction on a gun purchase form.

Hallie disclosed that she and Hunter had gone to treatment at a rehab facility in Pennsylvania on Oct. 6, 2018, six days before he bought the gun. 

When Lowell pressed Hallie about whether she had physically seen Hunter use drugs leading up to the day she tossed the revolver, she admitted she had not.

During the direct examination, Hallie told a federal court that she had become romantic with Hunter in either late 2015 or early 2016 — months after Beau’s death on May 30, 2015, from a brain tumor — and soon found out her new beau used the addictive street drug.

“I found it [crack] and Googled it because I didn’t know what it was,” Hallie said of the first time she saw the substance in her Wilmington home. “He told me what it was, crack cocaine.”

She further explained that she began using in June 2018, when the pair were on a trip in California and staying at the Roosevelt Hotel in Los Angeles.

When Wise asked Hallie “who had introduced you” to crack, the witness was quick with a response.

“Hunter did,” she answered. “It was a terrible experience I went through and I’m embarrassed and I’m ashamed. I regret that time of my life.”

Hallie said she had quit by August 2018, but Hunter continued to use.

During the questioning, the first son, wearing glasses, sat at the defense table and glanced between the witness stand and his notes in front of him.

Hunter’s wife, Melissa Cohen Biden, sat in the gallery next to Hunter’s aunt, Valerie Biden Owens. First lady Jill Biden, Hunter’s stepmother, had been in court for the first three days of the trial but was absent Thursday to attend D-Day commemorations in Normandy, France alongside her husband, President Biden.

Early in her testimony, Hallie said she and Hunter had known each other since they were in middle school and their romance blossomed gradually after Beau’s death.

She testified that Hunter didn’t deny using crack when she first confronted him. Later in their relationship, Hallie recalled, she saw him smoke it and even accompanied him to drug deals.

Despite Hunter’s dependence, Hallie saw him carrying on working and interacting with friends and family.

At times, he became “agitated [and] high-strung” when using, she recalled. “But other times [he was] functioning as well.”

At certain points, the witness recalled, she couldn’t tell when Hunter was using and when he wasn’t.

Hallie’s testimony, like that of Hunter’s ex-wife Kathleen Buhle and ex-girlfriend Zoe Kestan, seems to rebut Lowell’s argument in opening statements that “there is no such thing as high-functioning crack addicts.”

Hunter had drugs at his apartment in Washington, DC, and at the home the couple shared in Annapolis, Md., Hallie further claimed.

When they lived together, she said, his crack use became more and more frequent until he began using “daily.”

During the prosecution’s questioning, Hallie was shown a text that Hunter sent her on Oct. 13, the day after the firearm purchase, saying he was waiting for a “dealer named Mookie.” 

When asked what Hallie thought he was referring to, she answered: “That he was buying crack cocaine.”

Hunter sent her another message following day, Oct. 14, saying: “I was sleeping on a car smoking crack.”

However, when Lowell told Hallie that “you have no idea if he was on a car smoking crack or if he was just saying that,” she responded: “Correct.”

On Oct. 15, 2018, Hallie messaged Hunter: “I just want to help you get sober, nothing I do or you do is working. I’m sorry. I am afraid you are going to die.”

Wise asked Hallie at one point if she was afraid Hunter would overdose.

“Maybe,” she responded. “Or suicide … I didn’t know.”

Hallie also told jurors that on Halloween 2018, she had texted Hunter that her son, also named Hunter, was at the library with a leather pouch that contained drugs, apparently unbeknownst to the boy.

“I just went into the library and sitting next to Hunter was your brown leather pouch with a stem in it, laying in the chair next to him,” Hallie told the Biden scion in an accusing message.

The star witness was accompanied to court Thursday by Ohio financial broker John Hopkins Anning, whom Hallie married this past weekend.

“It’s not a great way to start the honeymoon,” Anning joked to NBC News, before adding that testifying was “very hard” on his new wife.