The fan-favourite song appeared on her latest record, released earlier this year (20), and on her big day on Tuesday (29Sep20) she thanked fans for their continued support with her latest visual.
In the clip, Halsey takes a look back on her life alongside home movie footage. The visual was helmed by her tour videographer and music video director Peter Donaghy.
"Honoring the tradition of presents for you on my birthday. Here's a special music video for '929' you guys have made me who I am today," she wrote on her Instagram page.
"Manic" was a massive hit on both sides of the pond upon its release in January and spawned the hits "Without Me", "Graveyard", and "You Should Be Sad".
The number "929" referred to her exact birthday as she was born on September 29, 1994 at 9:29 A.M. She explained before the album release, "I really was born at 9:29 a.m. on 9/29. You think I'm lying, but I'm being dead serious. [Laughs] I'll prove it."
She also said she wrote the album during a manic episode of her bipolar disorder. She described the mania as "that thing in the back of our minds that drives us to outrageous thoughts. Like when you're driving a car and you're like [she mimes suddenly cutting over the wheel], or you're on top of a building, and you're like, 'What if I just jump?' You are controlled by those impulses rather than logic and reason."