Melissa Joan Hart feels "really guilty" about taking Britney Spears out clubbing when she was underage.

The 48-year-old actress was playing the title role on the sitcom 'Sabrina, the Teenage Witch' when the then-17-year-old Britney landed a guest spot on the show at the start of her pop career in 1999 and the pair went out clubbing together but Melissa confessed that she "should have known better" than to encourage such behaviour.

She told 'Entertainment Tonight': "Britney and I got to do a lot of press together. And we had a lot of fun together during this time. I saw that she was just surrounded by people, never able to break free. And I was like, 'Hey want to come?'

"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.

"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.' And yeah - and I feel really guilty about that still to this day because I should have known better, being a big sister."

The former 'Clarissa Explains It All' star - who also made a cameo appearance in Britney's music video for 'You Drive Me Crazy' around the same time - has not maintained contact with the '...Baby One More Time' hitmaker, now 42, since they worked together in the 1990s but she did go to see her concert in Las Vegas some years ago and the pair did manage to briefly reunite.

She said: "I saw her when she was doing her Vegas residency a few years back, but she was doing her show so, you know, it was a quick hello backstage and that was it."