Every dark-pop hit with the LaRosa name attached traces back to one bedroom studio and one sibling partnership that started before either of them could drive. Isabel LaRosa writes, sings and directs. Her brother Thomas produces, mixes and masters nearly all of it. Four years apart in age, they have built two careers, and quietly seeded a third, out of the same small circle of trust.
Jazz Clubs, Then a Guitar in the Room
The origin story starts with their father, a hobbyist jazz saxophonist who wanted musician kids and got them by taking Isabel to jazz clubs and open mics from early childhood. By seven she was singing standards while Thomas, already playing guitar, backed her up. He started writing songs at 11, and Isabel followed soon after, the two of them writing together since she was still in elementary school. For most of her career, he was not just her producer, he was her only collaborator, period. "The only person I've worked with my entire life and the only person I've written with," is how she has put it.
He's the other half of my brain.
Every Credit Says the Same Name
Look at the production credits on Isabel LaRosa's biggest songs and one name repeats: Thomas LaRosa, producer. He built the sound behind her breakout "i'm yours" (2022), which has streamed more than 420 million times on Spotify alone, and he has stayed on the boards through "Favorite," "Pretty Boy," "Muse," "Older" and "My Girl." Even when outside writers entered the picture for her 2025 debut album Raven, including Amy Allen and Ian Kirkpatrick, Thomas remained attached, co-producing lead single "Home" alongside Kirkpatrick and mixing several other album tracks himself.
The Third Career Nobody Names
The LaRosa production line does not stop with Isabel. Thomas is also the producer behind Ari Abdul's entire early catalog. Thomas co-wrote and produced Ari Abdul's debut EP Fallen Angel, and was featured on the single Sinners. That collaboration began, according to accounts of the era, when Ari first started recording "Babydoll" in 2021 after her best friend, Thomas LaRosa, asked her if she wanted to make a song. She reluctantly agreed, and recorded it. Isabel co-wrote the finished version alongside Thomas and Ari, and the song went on to earn a RIAA Gold certification, Ari Abdul's first. The pattern repeated on "Stay," "Taste," "HUSH," "Cursed" and "HELLGIRL," all carrying Thomas's production stamp, which means the two most recognizable voices in the current dark-pop wave, Isabel LaRosa and Ari Abdul, were built inside the same small studio, by the same producer, often with the same co-writers in the room.
Stepping Out From Behind the Boards
While Thomas has spent years shaping other people's songs, he has also been releasing his own. His solo catalog includes viral singles such as "Good Girl" (2023), "Like a Dream" and "Dangerous," tracks that built real traction on Spotify and TikTok in their own right, delivered in an emotional hip-hop and pop style built around honest, personal lyrics about love and loss. He kept the momentum going into 2026 with the single "Back to the Start," released May 15, 2026. It is a quieter, indie-pop-leaning credit that suggests Thomas is no longer content to stay entirely behind the glass.
The Circle Widens, Carefully
Isabel's 2026 EP Promising Young Woman, released June 5 through RCA and Slumbo Labs as a six-track project, marks the clearest sign yet that the once-closed LaRosa writing room is opening up, without pushing Thomas out. Asked about one of the EP's standout tracks, she described the session plainly: "I made it with, obviously, my brother Thomas, and Zhone produced on it," adding that she wrote the song with Sasha Alex Sloan. It is a small but telling shift: for the first time in her career, a co-producer sits in the credits alongside her brother rather than replacing him, on a project one reviewer called darker, sharper and more emotionally expansive than anything she has released before.
I made it with, obviously, my brother Thomas, and Zhone produced on it.Isabel LaRosa, OnesToWatch
Why the Bond Still Holds
None of this dilutes what makes the LaRosa sibling arrangement unusual in an industry built on rotating rosters of hired producers and topline writers. Isabel has called Thomas "such a massive part of the creative process, I would not be here without him," and the receipts back that up: every era, every EP, every viral clip that turned into a certified record has his name on it somewhere. Even as she brings in Grammy-caliber collaborators and he builds a solo run of his own, the two keep landing back in the same room. That is the real throughline of the Slumbo Labs story, not a label, not a genre tag, but a brother and sister who decided, before either was old enough to sign a contract, that they would build this together, and mostly haven't stopped.