Two years after she performed at a New Year's Eve concert for the family of Muammar Gaddafi, Mariah Carey says she feels "horrible and embarrassed" about the incident. Despite ignoring calls to donate the $1m (£615,500) she reportedly received for the gig, Carey promised that a future single, Save the Day, will raise money for human rights.

"I feel horrible and embarrassed to have participated in this mess," Carey told the Associated Press yesterday. The singer's comments were more doleful than statements made this week by Nelly Furtado and Beyoncé, addressing similar concerns. All three pop stars had performed at private events for the Gaddafi family, earning massive pay cheques. Beyoncé and Carey both claimed that, at the time, they had no idea who had hired them.

"I was naive and unaware of who I was booked to perform for," Carey explained. The singer is one of just 22 people followed on Twitter by Muammar Gaddafi's son, Saif al-Islam Gaddafi. "Going forward, this is a lesson for all artists to learn from," Carey said. "We need to be more aware and take more responsibility regardless of who books our shows. Ultimately, we as artists are to be held accountable."

Carey did not confirm how much she was paid for 2008's four-song set, which took place on St Barts in the Caribbean, nor did she pledge to donate the money to charity. But the 40-year-old has announced that a forthcoming single, Save the Day, will benefit causes that promote human rights.

"Mariah has and continues to donate her time, money and countless hours of personal service to many organisations both here and abroad," said her publicist, Cindi Berger. The singer has previously donated royalties from songs such as One Sweet Day, recorded with Boyz II Men, and Hero, which was later an X Factor charity single.

Nelly Furtado is so far the only artist to have donated their fee from the Gaddafis following this month's uprising in Libya. Beyoncé claims that she gave away her $2m (£1.23m) commission last year after discovering it came from Muammar Gaddafi's son, Mutassim. Other stars who allegedly performed for the Gaddafi clan, including Usher, Timbaland and 50 Cent, have not responded to calls for their fees to be donated.