NICOLE RICHIE’s hubby Joel Mad­den is begging the skeletal beauty to fatten up so they can expand their family, sources say.

The 32-year-old fash­ionista, who has battled eating disorders in the past, shocked onlookers at the re­cent American Music Awards with her emaciated frame and what appeared to be her protruding rib cage.

“Nicole has lost seven pounds in the past two months, which is seriously worrying for everyone,” a longtime pal told The ENQUIRER.

“She’s had trouble keeping weight on for years, and she always watches her­self. But it looks like she’s let things slide again and Joel’s totally freaking out.”

Back in 2007, the 5-foot-1 star dropped down to 83 pounds and wound up at the former Beau Monde treatment center in Southern California for treatment of anorexia and sub­stance abuse, although at the time she publicly denied that she had an eating disorder. She put on some weight and appeared to be healthy for a while. But in the past few months she lost weight, and one expert says she looks to be less than 90 pounds again, maybe as low as 87.

Meanwhile, Nicole has been telling pals that she and “Good Charlotte” rocker Joel – parents of daughter Harlow, who turns 6 on Jan. 11, and 4-year-old son Sparrow – want to add one more child to their brood, said the source.

“Joel has always wanted a ton of kids, and he’s desperate to give Sparrow a little brother,” the source added.

“He’s thrilled that Nicole is on board, but he’s told her to fatten up.

“He wants her pregnant before he heads to Australia for ‘The Voice’ next year. But unless Nicole puts on at least 10 pounds, that’s looking less likely.”