"Kate Plus 8" star Kate Gosselin's kids are allegedly in danger because of her choice of a new boyfriend who apparently has a "dark past," according to the latest from the tabloid Star magazine.

On its June 15 issue, Star magazine alleged that the eight children of the "Kate Plust 8" star are at risk because their stepfather, millionaire Jeff Prescott, "may be dangerous."

Documents obtained by the tabloid revealed that Jeff Prescott's ex-wife has filed a restraining order against Kate Gosselin's beau in 2005 "because he got possessive and scary."

But Kate Gosselin allegedly appeared to be unconcerned because she's "blinded" by her love for the millioniare, and even believed him when he told her that the restraining order was "no big deal."

Now, the ex of the "Kate Plus 8" star Kate Gosselin, Jon Gosselin, is worried about their kids.

"Jon doesn't want this guy anywhere near his kid. Nobody would be shocked if a new custody battle happens as Kate's relationship grows more serious," the source claimed.

Meanwhile, Jon Gosselin is fighting for custody for Hannah who allegedly complained of abuse in the household in Wernersville, Pennsylvania.

"Jon has just filed papers asking a Pennsylvania judge for primary custody as well as a review of the child support order that is in place. Primary custody is currently Kate's, and Jon is required to pay $21,000 a month in child support," People said back in April.

It was reported before that Jon Gosselin took his daugther Hannah with him for four days without the expressed consent of Kate Gosselin, who has primary custody of their kids.

"While Hannah has since returned to Kate's home with her siblings, fellow sextuplets Aaden, Collin, Leah, Joel and Alexis, and 14-year-old twins Mady and Cara, Jon is said to be following through with his plans to modify their custody agreement," the report said. "If he succeeds, he will reportedly request TLC 'put a stop to filming' his family for 'Kate Plus 8.'"