Amanda Seyfried Flashes Underwear 'While We're Young'!

Amanda Seyfried goes bottomless with bright underwear while filming scenes for her upcoming film While We’re Young on Tuesday (September 24) in New York City.

The 27-year-old actress was joined on set by Naomi Watts, who was spotted holding hands with co-star Ben Stiller.

PHOTOS: Check out the latest pics of Amanda Seyfried

While We’re Young centers on “an uptight documentary filmmaker and his wife who find their lives loosened up a bit after befriending a free-spirited younger couple.”

Last week, Amanda and her boyfriend Justin Long grabbed a morning coffee with her beloved pet pooch Finn in the Big Apple.

FYI: Naomi is wearing the Elizabeth and James Bourne Jacket.

20+ pictures inside of Amanda Seyfried flashing her bright underwear on the set of While We’re Young…