Lena Dunham's no stranger to going topless, whether it’s for her HBO hit Girls or just for fun, but on Friday, she stripped down for a cause.
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The actress posed for an Instagram pic with her adorable dog, Lamby, covering up everyting but the tattoo below her right arm.
"We heard a rumor it's #NationalMuttDay ❤️" Dunham captioned the pic.
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It’s been an eye-opening week on Instagram for Dunham. On Monday, she posted a paparazzi photo of herself jogging and opened up about changing her attitude about the exercise.
"@jennikonner is directing the season finale of Girls and decided that as Hannah evolved so would her run, so she got me a training session with Matt Wilpers from Mile High Run Club," Dunham explained. "Within an hour I had a different relationship to this formerly torturous activity. I felt strong, swift and proud."
WATCH: Lena Dunham Gets a Running Coach: I Used to 'Run Like a Wounded Baby Pterodactyl'