German Penthouse -- Horror Star Unveils Schnitzel at 40

Jennifer Blanc Biehn -- wife of Terminator star, Michael Biehn -- is giving herself a special 40th birthday present -- a full nude pictorial in Penthouse Germany.

Biehn, who was in "Dark Angel" back in the day, was 39 when she shot the spread ... but will be 40 when the May issue is released.

Jennifer tells us she wants to show women you can be proud of your body at any age.

Translation: she wants to prove she's still got it.

As for any special grooming before the shoot -- Jennifer says she keeps a clean palette at all times. However she did need a friend to keep her "nipples hard with a cold Red Bull can."

Das ist was freunde sind.