Transcript for Prince William welcomes Harry to 'sleep deprivation society that is parenting'
Now, to the royal baby tonight. A boy for Harry and Meghan, of and tonight, we now hear from William and Kate. ABC's linsey Davis from Windsor castle. Reporter: A royal celebration today in honor of the newest member of one of the most famous families in the world. The queen at Windsor with prince Philip this afternoon may be the first royal to meet the baby. Congratulations, another great grandchild. I know. How many of them have you got now? Eight. Reporter: Both will and Kate in the dark about the big question that still looms. We look forward to meeting him and to finding out what his name's going to be. Reporter: Tonight, bets are on Alexander as the favorite followed by Arthur, James and Spencer, princess Diana's maiden name. Harry, notably close to his late mother. But the royal highnesses remain tight-lipped, and baby Sussex relatively quiet, as well. The couple is said to have enjoyed a peaceful first night. Prince William warning that won't last. I'm very pleased and glad to welcome my brother to the sleep deprivation society that is parenting. Reporter: For now, Harry absolutely gushing in the first hours of fatherhood. It's been the most amazing experience I can ever possibly imagine. We love seeing Harry like that. Lindsey Davis with us tonight from wind sour. Tomorrow the big day, linsey? Reporter: Tomorrow is the big reveal, David. We're finally going to get a chance to see the baby, the moment so many have been waiting for with baited breath. Harry and Meghan doing things their own way, spending the time together privately first as a family before stepping back out into the spotlight with their new bundle of joy. Linsey Davis across the pond for us tonight.
This transcript has been automatically generated and may not be 100% accurate.