Britney Spears had panic attack when she ran into ex Justin Timberlake before painful 2007 VMAs performance

Britney Spears attempted make a comeback at the 2007 MTV Video Music Awards when she performed her hit “Gimme More.”

The live performance came following her multitude of personal struggles, such as her divorce from Kevin Federline and the moment that she spontaneously shaved her head.

To add to her worries, she bumped into ex Justin Timberlake at the awards show just before she graced the stage — and the moment gave her much anxiety.

In her new memoir, “The Woman in Me,” the pop singer, 41, detailed the awkward incident, writing: “It had been a while since I’d seen him.”

“Everything was going great in his world,” the “Toxic” crooner penned.

Spears went on in her book: “He was at the top of his game in every way, and he had a lot of swagger. I was having a panic attack. I hadn’t rehearsed enough. I hated the way I looked. I knew it was going to be bad.”

The “Crossroads” star further discussed her appearance at the music ceremony, noting that “nothing was going right” backstage.

“There was a problem with my costume and with my hair extensions. I hadn’t slept the night before. I was dizzy. It was less than a year since I’d had my second baby in two years but everyone was acting like my not having six-pack abs was offensive,” Spears said.

She added: “I couldn’t believe I was going to have to go out onstage feeling the way I felt.” As fans remember, her chaotic presence garnered backlash, with the Post calling it “totally lame” and a “ditzy disaster” at the time.

The “Pieces of Me” crooner sighed: “I went out there and did the best I could at that moment in time, which — yes, granted — was far from my best at other times. I could see myself on video throughout the auditorium while I performed; it was like looking at myself in a fun-house mirror.”

Spears’ performance featured her lip-syncing and very weak dance moves. The A-list audience watched in horrified shock at her singing, with stars such as Diddy rolling his eyes and 50 Cent looking worried.

Even Timberlake, 42, seemed shook and his mouth stayed agape throughout the song.

“Justin glided down the runway,” she explained. “He was flirting with girls in the audience, including one who turned around and arched her back, shaking her breasts as he sang to her.”

The “Cry Me a River” singer, meanwhile, had a big night, winning the trophy for Male Artist of the Year and scoring a nod for Video of the Year.

He also took the stage to sing “Lovestoned” and “Give It Up to Me” with frequent collaborators/ 2000s music legends Timbaland and Nelly Furtado.

Spears and Timberlake famously dated from 1998 until 2002, with the mom of two even revealing in her memoir that she got an abortion when she fell pregnant with his baby when she was 19.