Not exactly a big secret once she took off her false lashes.
And, it's pretty obvious that a body double was used for the cleavage shots.
The ad is for the Wacoal (a lingerie company headquartered in Japan) Mood Boost-Up Bra, which adds 2 cup sizes, according to the YouTube page translation.
My main criticism — besides the bogus-ness — is that video is about 45 seconds too long. Also, bad, boring song choice.
This creative linchpin was much better executed last year in The Netherlands, where Hema smartly used androgynous supermodel Andrej Pejic to show off their line of push-up bras.