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Kimberly Stewart baby daughter Delilah Jack Osbourne lunch

Dressed in matching mommy-and-me moccasins, Kimberly Stewart showed off 4-month-old daughter Delilah for the first time in public, as she met Jack Osbourne for a lunch date in Beverly Hills, on Saturday.

No doubt the proud mamma was offering Jack some parenting advice -- he's about to become a daddy for the first time next year!

Osbourne broke the news that his fiancée, Lisa Stelly, is expecting their first child during an interview with Piers Morgan in October.

Jack and Kimberley actually dated from 2003 through 2004, and have remained close friends since their split.