"Our passenger has touched down and arrived. Welcome to our world. There has not been a more fulfilling day," Barash tweeted.
The couple, who married in June, shared photos of their new addition on Thursday.
Just the three of us...well, the Queen, the Princess and a dad's hand. pic.twitter.com/2oR0ErZHEQ— Brandon Barash (@BrandonBarash) January 9, 2014