Clad in a sexy black Marciano jumpsuit, Manolo Blahnik heels and a big smile, Sparks stayed close to her man as Derulo introduced the songs on "Talk Dirty" to the crowd at 1Oak in Los Angeles.
"I'm so proud of my baby and what he's accomplished," Sparks, 24, tells PEOPLE. "I've been with him every step of the way and I'm so proud to be here tonight."
The American Idol champ beamed as Derulo, 24, headed onstage and stood behind the turntables to announce his tracks.
"I really wanted to be myself on this record," the pop star said before raising a glass with Sparks and playing his tracks one by one for the crowd.
Sparks stood right behind the DJ booth as the first song, "Wiggle," played, looking every bit the supportive girlfriend while shaking her head and smiling.
She sang almost every word to every song, and the romantic duo connected even more when he played his first love song, "Vertigo," which features Sparks. During the track she held onto his arm with her head on his shoulders. Later, she embraced him by pulling him in with her arm around his waist.
At one point she gazed into his eyes and they both mouthed the lyrics together.
After Derulo played his songs for the crowd, he and Sparks danced and mingled as the DJ continued to spin tracks at the club.
– Raha Lewis