But it ended up being a "huge disappointment" because of rival Hello! magazine's coverage using unauthorised pictures of the New York wedding in November 2000.
Martin Townsend, giving evidence at a hearing to decide the damages Hello! must pay its rival and the Douglases, told Mr Justice Lindsay that the Beckham issue had been "extremely successful".
Sales of the first David Beckham and Victoria Adams wedding edition in July 1999 quadrupled sales of OK! to about 1,500,000 copies.
Mr Townsend said: "We had a telephone call to the office from a newsagent about a fight that had broken out between two ladies fighting over the last issue.
"At that point we realised we had something quite phenomenal on our hands. There was a realisation that we had underestimated the popularity of it all."
OK! had paid £1 million to the Beckhams for exclusive coverage of their wedding and had signed a deal with the Douglases for the same amount.
Alastair Wilson QC, representing the Douglases and OK!, asked Mr Townsend how he thought the Douglas wedding compared with the Beckhams.
"It was much, much bigger," he replied.
"The Beckham story was a great event at the time but there was always an element in my mind, an element of gamble about it."
He said they had signed the contract with David Beckham in 1998 just before he was sent off in a World Cup game and his popularity had fallen massively, with the Press baying for his blood.