Rihanna was notably absent at the 2014 Grammys when her Unapologetic album nabbed the award for Best Urban Contemporary Album.
On Tuesday's Good Morning America, the "We Found Love" singer said she was "so shocked—really" about winning a Grammy (her seventh one to date).
"I was at home and one of my friends hit me and said, 'You just won a Grammy,' and I was like, 'What?'" she said. "And when I went on the Internet I just saw Unapologetic! It was quite an emotional moment surprisingly, but I was in shock. I'm excited. It was a good feeling to still be that excited at this point in my career."
The 25-year-old singer also opened up about her new role as M.A.C Cosmetics' philanthropic partner and how "100 percent—every penny you spend" on the Viva Glam Rihanna campaign lipstick or lip glass "goes to the M.A.C Aids Fund."
The organization has already raised $325 million towards the awareness and prevention of HIV and AIDS, and the singer said the "goal is to raise $40 million with the Viva Glam Rihanna Campaign."
"The thing about M.A.C as a brand that I really love and embrace is that they don't judge. They're not here to say 'Be perfect.' They want you to have fun—as well as myself—I want you to have fun, I love to have fun. But you have to be responsible. You have to be safe, protect yourself. You have to look out for yourself, because nobody else can do that for you."