The 26-year-old creator and star of hit U.S. TV drama Girls appears to be opening up about losing her virginity in the controversial commercial, titled Lena Dunham: Your First Time, but it soon becomes clear she's talking about her first time in the voting booth - and the fact she wants others to enjoy their first voting experience by supporting incumbent President Barack Obama.
In the ad, which has been posted on YouTube.com, she says, "Your first time shouldn’t be with just anybody. You want to do it with a great guy... Someone who really cares about and understands women. A guy who cares whether you get health insurance and specifically whether you get birth control. The consequences are huge."
Dunham also uses the spot to blast the Democrat's main rival, Republican candidate Mitt Romney, for his anti-gay stance, stating, "You don't want a guy who... thinks that gay people should never have beautiful, complicated weddings...".
And she insists stepping into the voting booth for the first time in 2008 was a life-altering moment: "My first time voting was amazing. It was this line in the sand; before I was a girl, now I was a woman... I voted for Barack Obama."
The advertisement has prompted mixed reactions from YouTube.com viewers, with some praising Dunham's cheeky approach and others accusing her of damaging Obama's re-election campaign, but the actress stands by the clip and insists it sends a strong message to those in her age bracket.
Taking to her Twitter.com blog to respond to critics, she writes, "The video may be light but the message is serious: vote for women's rights."
Americans will head to the polls on 6 November (12).