The trio went to Jinkys Kanan Cafe in Agoura Hills, with a Keeping Up with the Kardashians camera crew along for company.
Jenner was dressed down in jeans that seemed to hang on his thin frame, and a V-neck sweater. He left his usual baseball cap at home, though, allowing his long hair to flow freely.
As RadarOnline.com exclusively reported, a plastic surgeon, who has not worked with the reality star, says it appears Jenner has had hair transplant surgery.
"His frontal hairline appears thicker and much lower than in the earlier photos taken of him," Dr. Richard Chaffoo told us.
After the lunch, the girls then joined momager Kris Jenner -- who was all smiles -- to shoot additional scenes for their show of them grocery shopping.