There's a new member in the So You Think You Can Dance family.Cat Deeley, the show's host, announced in a tweet Tuesday that she's given birth to a healthy baby boy. Deeley and her husband, comedian Patrick Kielty, welcomed their son last week. The couple announced in September that they were expecting."Beyond delighted to announce the birth of our baby boy last week," Deeley tweeted . "All doing well & we couldn't be happier... 3 really is the magic number!"Deeley didn't reveal her son's name in the tweet, referring to him only as "our baby boy." The baby is the first child for the couple, who tied the knot in 2012.We're wishing all the best for Deeley and Kielty in this joyful time.