Selena Gomez Sings 'Cry Me A River,' 'I Knew You Were Trouble' At UNICEF Concert (VIDEOS)

Selena Gomez might be using music to send a message to her ex-boyfriend, Justin Bieber.

The former Disney star headlined the third annual UNICEF charity concert on Saturday night at the Best Buy Theater in New York City. She performed "Round and Round" and "A Year Without Rain," but it was Gomez's decision to sing "Cry Me A River" that raised eyebrows, notes HollywoodLife.

“I’ve been through a lot the last couple of months," she told the crowd, according to HollywoodLife, at her first live concert in over a year. "It’s been sad and cool, but interesting. This song definitely speaks to me."

The 20-year-old then broke into a cover of "Cry Me A River," Justin Timberlake's 2002 breakup song, inspired by his failed relationship with Britney Spears. The song definitely resonates with the heartbroken, with lyrics like: "You don’t have to say, what you did/ I already know, I found out from him/ Now there’s just no chance, for you and me/ There’ll never be/ And don’t it make you sad about it."

Gomez even changed up the lyrics to make the song fit from a woman's perspective.

"Cry Me A River" was certainly a loaded choice for Gomez to make. Not only is it a breakup ballad, but Bieber also sang an acoustic version of the song at a concert in Boston after the couple's first split back in November.

And it wasn't her only nod to breakups.

The "Spring Break" actress also covered Taylor Swift's "I Knew You Were Trouble," telling the sold-out crowd, "It's by my best friend in the entire world and if anybody has felt anything painful to their heart, they know who this girl is. Sing along if you know it."

In an October interview with "Good Morning America", Swift explained the song is about "kind of being frustrated with yourself because you have your heart broken and you knew when you first saw that person you saw all these red flags and you just went for it anyway."

Watch Selena Gomez perform "Cry Me a River" And "I Knew You Were Trouble" below.