The Nickelodeon child star killed while crossing a Brooklyn street was struck by two vehicles — and neither driver stopped, cops and police sources said Saturday.

Kianna Underwood, 33, was crossing Pitkin Boulevard at Mother Gaston Boulevard in the crosswalk but against the light on Friday morning when she was first hit by an SUV, police said.

She was then run over by a black and gray sedan of an unknown make and model as she lay on the ground, cops said. That vehicle dragged her “several hundred feet,” a police source said.

Both drivers fled after hitting her and neither have been apprehended as of Saturday afternoon, cops said.

Residents in Brownsville, where the crash occurred, recalled seeing Underwood in the neighborhood.

“She had a beautiful heart.  She was a sweet heart, she really was,” said Keith Speller, 60.

“I’ve just seen her a couple days ago. She saw me, she came over and gave me a hug and kiss on the cheek and she said, ‘I love you’ and she’d come and see me again,” he added.

“Two days later she was gone.”

Rhonda Millington said Underwood was in the area frequently.

“Life is long but people shorten it,” the 57-year-old said, recalling how Underwood had on a pair of fancy, knee-high boots the last time they spoke and that the former actress playfully promised to get her a pair.

“If that car didn’t hit her, she’d be here with us,” Millington added. “She shouldn’t die like that. I don’t know who did it but nobody, not you, not me should die like that. That’s very sad.”

Underwood’s death comes after one of her former “All That” castmates exposed the tragic reality she was living in.

Angelique Bates, who starred on the musical-comedy with Underwood in the early aughts, blasted Nickelodeon execs and former castmates on Instagram in 2023 for not stepping up to help Underwood, according to TMZ.

Bates claimed her co-star was homeless in New York, which police sources confirmed to still be the case at the time of her Friday death.

In 2019, Underwood had apparently gone missing, according to a Facebook post in which a friend pleaded with people to contact the actress’s family if she was spotted, according to a thread on X. 

The writer claimed the child-star was suffering from mental illness, though further details weren’t given. 

By 2021, people who knew Underwood shared their concerns about her online — including that she was out in the streets fighting — with friend Brian Tomkin writing “she’s just out of control and out [of] her mind out here, like 2 different people, she [is] not even like that.”

“She is a sweetheart but [is] out here fighting bitches and all that not caring about life,” the worried friend continued. 

After news of Underwood’s tragic death made headlines, Bates paid tribute to her castmate on Instagram.

“Y’all have no idea how much this one hurts…Sick to my stomach….So many people failed baby girl,” she wrote.

Followers of Bates mourned the loss of the child-star, acknowledging the struggles Underwood faced toward the end of her life.

“Omg it was bad enough that she was living on the streets. But man condolences goes out to her family,” one wrote.

Lisa Foiles, another castmate from the 2005 season of “All That” also mourned Underwood late Friday, sharing on her Instagram story, “I heard the news and I am absolutely devastated. Still processing it. I’m utterly heartbroken.”

Underwood’s long-time friend Johnny Diaz, told The Post through tears, “It’s hard to sink in.”

“She was super talented, super passionate and super caring. She was loving and kind…she radiated love,” Diaz, 36, said of his pal of 20 years.  

Diaz knew the former-actor was ‘going through some struggles,’ and had battled isolation during the Covid-19 pandemic.

The child-star’s grieving dad declined comment and requested privacy. 

Underwood, who appeared in seven episodes of the final season of “All That” and featured in a number of television shows and movie productions between 1999 and 2005, was homeless, police sources told The Post.

Additional reporting by Jennifer Bain, Khristina Narizhnaya, Georgett Roberts and Sofia Poznansky