Update: Rihanna Says Chris Brown Was Her First Big Love & More In Upcoming Interview This Week On 20/20!

Nine months after her fight with Chris Brown, Rihanna finally opens up about that night.

"This happened to me. … It can happen to anyone," the singer, 21, tells Diane Sawyer in an interview airing Thursday on Good Morning America and on 20/20 on Friday.

Rihanna says it was particularly difficult because of the special place Brown held in her heart: "He was definitely my first big love."

Chris Brown is serving his sentence and working on new music, his album "Graffiti" will drop Dec. 15; and Rihanna is releasing her fourth album "Rated R" on Nov. 23. The album's first single "Russian Roulette" debuted last week.