Birthday girl Jennifer Aniston went on Ryan Seacrest's KIIS FM show Friday, and dished about her ab envy...

In fact, the actress, who was talking to Seacrest about Just Go With It seemed much more interested in praising her co-star Nicole Kidman’s anatomy than in promoting her new movie!

AUDIO: Jennifer Aniston Gushes About Nicole Kidman’s Abs

"I walked up to her and said I'm sorry, can I touch [your stomach]," Aniston told Seacrest. "I had to touch it. Is that spray painted? What is that? And that's rock solid...I think it's 9-eight packs."

Aniston, who is equally famous for her own rock hard abs and killer bikini body, told Seacrest that obtaining a mean mid-section isn't rocket science.