"Don't tell me to stop loving: you can't do that and I can't either," Googoosh sings in "Behesht" (Heaven).
Googoosh was Iran's first pop diva, though the 1979 revolution interrupted her singing career for two decades until she left the country. Her music has remained popular with Persian speakers everywhere and underground in Iran, where her status is comparable to that of Madonna.
Navid Akhavan, an Iranian-born German who wrote and directed the video for the song, said it has been viewed by more than a million Iranians online or via illegal satellite channels since its Valentine's Day release, and was clicked on half a million times in the first 24 hours.
"That shows the subject is something that, if you're for it or against it, draws attention," Akhavan said in an interview with The Associated Press during a visit to Amsterdam.
Government-controlled newspapers have criticized the video, and labelled Googoosh "anti-revolutionary" because of it — the equivalent of accusing her of treason.
Farinaz Aryanfar, a Dutch-based Iran expert not associated with the project, said she had viewed the video soon after it came out and was caught off-guard by the twist at the end. She said that would likely be true for all Iranians.
"In any perspective you look at it, it's taboo-breaking," she said.
She said that it's impossible to know how many people in Iran have seen the video, or to make generalizations about how it has been received. But she had seen it widely shared via social media, which Iranians access remotely in order to avoid government censorship filters.
She said she thought the video's release is on the whole "a good thing."
"Googoosh is so famous, there are so many people who love her, that if a fan watches this video — it makes you start thinking," she said.
Navid said he had received an outpouring of thanks from gays in Iran, who feel that affirmation of their existence by a celebrity of Googoosh's status is a major breakthrough.
He said the video and its message were calibrated to engage with the broadest swath of Iranians possible, raising the issue of homosexuality but focusing on love rather than sex or nudity.
"I thought this would be the perfect time, with this medium of the music video, with this icon Googoosh, to open the conversation about it and to say: freedom to love for all is something that we should understand, and should be for," he said.
YouTube version, with English subtitles: http://www.youtube.com/watch?v=378BihV0kqU