Newly released films have been downloaded illegally in huge numbers since stay-at-home lockdown measures were imposed in the UK.
According to Fact, the UK's intellectual property protection organisation, overall links to illegal streaming sites doubled between February and April.
And for some recently released films, it had trebled.
Kieron Sharp, chief executive of Fact, said it was no surprise.
"It's essential to remember that the only legal way of watching films is through the official providers.
"Every pirated link that we detect denies the rights holder of revenue they are entitled to, and also threatens investment in future content."
Fact did not name the films that had seen particular spikes in streaming but did encourage people to report illegal sources they come across to Crimestoppers.
Its findings are reflected in other studies.
Piracy-tracking firm Muso found traffic to illegal streaming and download sites rose by nearly 60% during March. It noted more than 300 million visits to piracy sites in the UK, and more than one billion in the US.
Oscar-winning film Parasite saw demand rise 240% on illegal streaming sites at the start of the pandemic. The 2011 film, Contagion, about a virus outbreak, saw a rise in piracy streaming visits of 151%.