Spurs posted a tweet on Monday of a sign in from Buckingham Palace which read: "Tottenham Hotspur Football & Athletic Co Ltd is delighted to announce the arrival of a new Royal."
Spurs announced later in the day that Aurier's contract was terminated by mutual consent.
Barca coach Ronald Koeman had expressed a desire to keep Emerson, but the club's dire financial situation meant they were willing to allow the defender to leave.
Emerson, 22, re-joined Barca in a €9m deal this summer after spending two-and-a-half seasons on loan at Real Betis.
The Brazil international has featured in all three of Barca's league games this season.