The Sinner actress debuted her new cut and colour at the 2018 Makers Conference in Los Angeles this week.
As much as we love Biel's lighter 'do, her husband Justin Timberlake loves it even more.
“My boo thang looks goooood!” the Man of the Woods singer, 37, wrote on Instagram.
Biel's hair colourist Tracey Cunningham took to Instagram to share a before-and-after video of the star's hair.
The celebrity hair stylist explained that she had been slowly dying the 35-year-old's hair lighter, but at the last minute she wanted to go really blonde.
"We only had an hour to do her! I felt like I was on a game show, and I had to beat the clock," she wrote.