The creator of Breaking Bad says piracy "helped" the show to become popular and increase "brand awareness".
Vince Gilligan said: "[It] led to a lot of people watching the series who otherwise would not have.
"The downside is a lot of folks who worked on the show would have made more money, myself included, if all those downloads had been legal."
According to Torrentfreak.com, the final episode was illegally downloaded more than half a million times.
The 46-year-old made his comments as part of Newsbeat's week long investigation into copyright.
The fourth series of Downton Abbey started in the UK at the end of September but doesn't begin in the US until January.
Gareth Neame, the programme's executive producer, said: "The three month delay between the UK broadcast, we air in September and we're not on in America until January, it is completely unrealistic in this day and age that there is such a long timeline."
He added that the 24-hour difference between when Game of Thrones is shown in the US before being screened in the UK was more realistic.
"There is a historic reason why we run later than the US, and it doesn't seem to affect our ratings.
"The last episode was the highest rated drama on television that night, so we can't look at that and say, well this delay is losing us viewers. It's not really having that effect."
Atlantis executive producer Johnny Capps said that illegal downloading is a "huge problem for programme makers" and they are "powerless with how to deal with it".
He added: "If a show keeps on being illegally downloaded then the value of the show is worth less, so therefore your budgets will go down and it will affect the show creatively.
"As programme makers, what you try and do is you try and make your product, your shows, available day and date globally. And that's very difficult to do, and in the first series of Atlantis that won't happen."
He also said "if people are downloading it, people are talking about it", which helps create fans and drive people to buy the DVD of the show.
"There is the problem of illegal downloads, we have to sort of face that, but as the series progresses and networks around the world buy into it, we'll be able to create a system where you can do day and date transmission.
"And when that happens it has been proved that the counterfeiting of shows goes down a lot."
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