updated 06/15/2011 AT 11:00 AM ET
•originally published 06/16/2011 AT 8:30 AM ET
The Duggar family just got even bigger – it’s a boy for Josh and Anna!
Josh, 23 – the eldest son of Jim Bob and Michelle Duggar – and his wife welcomed a new addition on Wednesday, four days earlier than expected, a source confirms to PEOPLE. The couple are not ready to release the name publicly yet, but they are staying with the “M” theme.
Weighing in at 8 lbs., 5 oz., he joins big sister MacKynzie, 20 months. And he’ll have plenty of doting relatives with 18 aunts and uncles – Jim Bob and Michelle’s children – whose lives are documented on TLC’s 19 Kids and Counting.