Da Vinci Code historians plan appeal
The officials said the appeal could take place later this year, but no specific date has been set.
The Bookseller reported the appeal was due to be heard early next year.
Random House, which won the copyright case earlier this year at the High Court in London, expressed disappointment at the decision by Michael Baigent and Richard Leigh to appeal.
"We have the utmost respect for the British legal system and acknowledge Baigent and Leigh's right to appeal the ruling in the DVC case," a Random House spokesman said.
"We regret, however, that more time and money is being spent trying to establish a case that was so comprehensively defeated in the High Court," he said.
The historian's lawyer in the original case, Paul Sutton, could not be reached for immediate comment.
A judge ruled in April that the central themes which the historians said Brown had copied from their 1982 book, The Holy Blood and the Holy Grail, were "too general" to be protected by copyright law even if they had been reproduced.
Brown, who testified during the month-long trial, had expressed astonishment that Baigent and Leigh filed the suit in the first place.
They faced a legal bill of more than £1 million ($2.47 million) after losing the case.
The Da Vinci Code has sold more than 40 million copies worldwide and been turned into a Hollywood hit starring Tom Hanks.