By Thom Geier
Updated February 13, 2009 at 10:58 PM EST

Dan Brown has completed his long-awaited (and long-delayed) followup to the 2003 mega-best-seller The Da Vinci Code, according to a Reuters report on an interview that Da Vinci Code film director Ron Howard gave to Entertainment Tonight on Thursday. Suzanne Herz, a spokeswoman for Brown’s publisher, Doubleday, released a statement saying only that Brown “is making great progress” and that the publisher could not yet announce a title or publication date. Brown’s new book is the third featuring Harvard symbologist Robert Langdon, who is played by Tom Hanks both in Howard’s 2006 film of The Da Vinci Code and in this May’s adaptation of Angels & Demons. The Da Vinci Code sold an estimated 70 million copies worldwide, so the prospect of Brown’s book heading to stores this year should give a boost to battered booksellers still reeling from one of the worst holiday sales seasons on record.