Nicole Richie's birthday party was lit — literally.

The Simple Life alum celebrated her 40th birthday Tuesday (Sept. 21). On Instagram, she shared a video of her blowing out the candles on her birthday cake... and her hair catching on fire in the process.

The video shows her leaning over the cake before her blonde, shoulder-length hair goes up in flames. Richie's friend quickly pats her hair to extinguish the flames.

Watch the wild moment, below.

Richie appeared to be alright after the hair catastrophe, and even poked fun at the moment in the post's caption: "Well… so far 40 is [fire emoji]."

Her famous pals commented their birthday wishes and expressed astonished at how she subdued the flames so quickly.

"HBD!!! I hope you're okay!" Ellen Pompeo wrote, while Nicole's younger sister Sofia Richie added, "OH MY F---ING GOD!!!!!!!!!! That's hot."

"Jesus Christ lolooll," Vanessa Hudgens replied, which Richie's brother-in-law Benji Madden wrote, "Happy Birthday Sis love you and thankful for you always. Stay Lit."

A hairstylist named Russel, who has seemingly worked with Richie before, was horrified and added, "STOP!!! AGAIN?"

Apparently, this isn't the first time Richie's hair has caught fire... but she has a plan for next time. "I'll start a Pinterest board for new haircuts. Start thinking of cute curly bobs," she responded to the hairstylist.

Meanwhile, her husband Joel Madden joked, "That's hot." He also paid tribute to Richie in his own sweet post where he wrote that she "made love feel timeless, I've forgotten how old we are."

Embarrassing Celebrity Moments