David Beckham's Boys' Night Out After Harper's Birth

By Jennifer Garcia and Alison Schwartz

07/12/2011 at 03:00 PM EDT

It was boys' night out for the Beckhams Monday.

Just a day after welcoming daughter Harper on Sunday (and adding another girl to their brood!), David Beckham took his sons to dinner while mom Victoria Beckham seemingly stayed home to tend to their newborn.

With kids Brooklyn, 12, Romeo, 8½, and Cruz, 6½, in tow – along with some of his wife's family in town from the U.K. – Beckham, 36, dropped in for a family dinner at West Hollywood's Fig & Olive restaurant.

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"Everybody was in a very good mood, and they left happy," a source tells PEOPLE.

Sitting in the restaurant's indoor terrace for two hours, the party of 11 enjoyed dishes such as filet mignon and olive oil-mashed potatoes.

"The kids seemed happy, but they are such boys," a source close to the family told PEOPLE of the Beckham children's reaction to the newest addition. "[It] will be interesting to see how they take care of their little sister."