Kathy Hilton Says So Sorry Jen Aniston for Pregnancy Tweet

Kathy Hilton has some words of regret for falsely impregnating Jennifer Aniston.

Kim Richards and Kathy were out Wednesday night at Craig's with Kyle Richards and Kris Jenner ... along with a sea of paps.

Kathy -- who turned 58 and was out celebrating her birthday -- eats crow after her cake for the Jen tweet.

Kim also gives us her take on Ben's recent rehab stint. You'll recall ... she's completed rehab herself a time or two.