The dog, a gift from Sen. Ted Kennedy of Massachusetts who owns several Portuguese water dogs himself, will make his big debut Tuesday afternoon.
The Washington Post reported in its online editions Saturday night that Obama's daughters chose the name Bo for the pup because first lady Michelle Obama's father was nicknamed Diddley. The name for the dog was an apparent reference to the singer "Bo" Diddley.
White House aides told the AP that the office of the first lady arranged an exclusive deal on the dog story with the Post. The officials, who demanded anonymity because of the deal with the Post on exclusive details, said the dog was not in the White House as of Saturday evening.
Throughout the day Saturday, celebrity Web sites and bloggers had been abuzz with rumors of the first family's selection of a Portuguese water dog; one site even claimed it had pictures of the future first pet.
The president, for his part, earlier had embraced the frenzy: "Oh, man, now, that's top secret," Obama joked Friday to reporters.
Obama promised his daughters a puppy during the campaign.
"This is Washington. That was a campaign promise," Obama said when he appeared on Jay Leno's talk show last month, as the audience roared with laughter. "No, I'm teasing. The dog will be there shortly."
The president and first lady had said their choice was down to either a Portuguese Water Dog or a Labradoodle because they were considered good pets for children who have allergies, as Malia does.