Melissa Joan Hart is opening up about why she feels "really guilty" over a past experience she had with Britney Spears, revealing that she took the "Toxic" singer to her very first club when they were younger.

Hart and Spears were both big names in the late '90s and early 2000s, with Spears even appearing as a special guest on Hart's iconic show Sabrina the Teenage Witch while the actress starred alongside the pop icon in the music video for "You Drive Me (Crazy)."

"Britney and I got to do a lot of press together. And we had a lot of fun together during this time," Hart recently told Entertainment Tonight.

The Melissa & Joey star, who is six years older than Spears, said they developed a sibling-like relationship during this time and she wanted to help the "Lucky" singer relax and "break free" from always being watched by taking her to a nightclub with some friends.

"I saw that she was just surrounded by people, never able to break free. And I was like, 'Hey want to come?'" she recalled. "I would go to a club every night — I love dancing and I loved going out, but I also knew to be responsible and, like, when to stop."

However, Hart's feelings on the matter have changed over the years, especially as Spears seemingly struggled with partying as her fame grew, with Hart saying now that she should have "known better."

"She was underage and young and — but I [was] just like, 'Let's go out. We're just gonna go out and have some fun,'" she said. "And yeah — and I feel really guilty about that still to this day because I should have known better, being a big sister."

ET notes that it was less than a decade after this time that Spears was placed in a conservatorship under her father, Jamie Spears, one that would last for 13 years before a judge officially ended the controversial arrangement in November 2021. She has since been very outspoken in her feelings regarding her family during this time and has opened up even more in her memoir The Woman in Me.

OPRAH TAKES A TUMBLE