Nicole Richie has reunited with her former best friend Paris Hilton — but some of her other friends are a tad worried about it.

They say that Richie — who has blamed her startling weight loss on nerves — is emotionally vulnerable these days, and not up to the sort of hard partying and manipulation that Hilton is famous for.

“Nicole is an insecure girl, and next to Paris she shines a little less,” a “pal” of the two told Life & Style Weekly. The two were clubbing at Los Angeles nightclub Area on Oct. 12, and Hilton left Richie alone much of the night to hobnob with her new sweetie, model James Neate, according to the mag.

“[Richie] could hardly keep her eyes open. Her hair was a mess. She looked bedraggled,” a source told the mag, but when Hilton rejoined Richie, she pulled her buddy onto her lap and shouted, “I love this girl. She’s like my sister!”

Some are claiming that the “friendship” is a ploy to get better ratings for their reality show, “The Simple Life.”

One source told L&S: “Nicole really believes that Paris is welcoming her with open arms, but everyone knows Paris has a tendency to put herself first.”