Shenae Grimes and Jessica Stroup by Michael Desmond/The CW Shenae Grimes and Jessica Stroup by Michael Desmond/The CW

The super-skinniness of 90210's new leading ladies Jessica Stroup and Shenae Grimes is evident even to the untrained eye. But their weight may be slipping so fast that it's prompting producers and costars to stage an intervention, a source tells Us.

"They want the girls to gain weight," the source reportedly said. "They are trying too hard to be skinny, and it's started to wear on them. It's just not healthy."

Another insider suggested that their bodies have shrunk since the show began. "The girls were all skinny when they started, but they're definitely thinner now." They added, "I heard some of the boys on the show are going to sit down with the girls and talk to them."

One doctor estimated that Stroup, 21 and 5 feet 8 inches tall, weighs 100 to 105 pounds, while 5-foot-3 Grimes, 18, may weigh in at 90 pounds.

Do you think the girls are too thin for their own good? Are younger women in Hollywood especially susceptible to the pressure of the camera? - Anna Dimond

Catch clips of the new 9-0 with our Online Video Guide.

" 90210 Reveals Kel's Babydaddy! But Will He Ever Appear on the Show?
" 90210 Wants More Shannen, Extends Jennie's Stay
" 90210 recaps: Get the scoop on all the episodes