Kevin Federline’s book sent Britney Spears into spiral that led to DUI arrest

Kevin Federline’s tell-all memoir, “You Thought You Knew,” sent Britney Spears into a “downhill” spiral that ultimately led to her DUI arrest on Thursday.

“But the truth is, this has been going on for a while,” a source close to the pop star told Page Six after she was taken into custody. “Her behavior has become increasingly erratic in recent months. She goes from being fine to being not.”

The insider continued, “It was the Kevin book that really sent her over the edge, and it’s been downhill from there. It really impacted her emotionally.”

The source also told us that Spears “feels like she gave Kevin everything that he wanted over the years” and “paid him so much money,” but he still “exploited her” with his memoir.

“He used her; he wanted to ruin her,” the insider said. “And that was a really hard pill to swallow; it absolutely killed her that someone would want to damage her so much.”

Spears, 44, was arrested for driving under the influence after she was spotted swerving her BMW in and out of traffic on Wednesday.

Page Six confirmed that the “Oops! … I Did It Again” singer was handcuffed by the California Highway Patrol in Ventura County, Calif., around 9:28 p.m. local time and booked at 3:02 a.m.

Spears was also taken to the hospital to get blood drawn so officials could determine her blood alcohol content. She was released from police custody at 6:07 a.m. Thursday, and has a court date scheduled for May 4.

The “Toxic” hitmaker’s DUI arrest came five months after Federline released his bombshell book.

Federline, 47, made many shocking claims in the more than 200-page memoir, including allegations that she did cocaine while breastfeeding their two sons and often displayed “erratic behavior” like standing in their sons’ doorway at night holding a knife.

The backup dancer-turned-DJ also claimed that Spears drank while pregnant, and he expressed concerns that the pop superstar’s life was “racing toward something irreversible.”

Spears, who has denied Federline’s allegations, called the “constant gaslighting” from her ex both “extremely hurtful” and “exhausting” in an X post just ahead of his book’s release.

She also accused Federline of making a “profit off [her] pain” with his memoir.

“Trust me, those white lies in that book, they are going straight to the bank and I am the only one who genuinely gets hurt here,” the “Stronger” singer tweeted in October regarding her ex’s allegedly false and harmful narrative about her.

Spears and Federline tied the knot during an impromptu ceremony in Studio City, Calif., in September 2004.

They welcomed sons Sean Preston, 20, and Jayden James, 19, before separating in 2006 and finalizing their divorce the following year.

Meanwhile, the “Womanizer” singer’s manager called her DUI arrest an “unfortunate incident that is completely inexcusable” in a statement to Page Six on Thursday.

“Britney is going to take the right steps and comply with the law, and hopefully this can be the first step in a long-overdue change that needs to occur in Britney’s life,” her manager, Cate Hudson, shared. “Hopefully, she can get the help and support she needs during this difficult time.”

Hudson also said that Sean and Jayden “are going to be spending time with” the Grammy winner in the wake of her arrest, and her “loved ones are going to come up with an overdue needed plan to set her up for success for well-being.”