Naomi Watts and Liev Schreiber Take Alexander Out in Berlin

Actors Naomi and Liev Schreiber take their baby son, Alexander, for a walk in Berlin.

Naomi Watts Out with Son Alexander in London

New mom Naomi Watts heads out in London with son Alexander, almost 3-months.

Naomi Watts Post-Baby Fashion Secret

New mom Naomi Watts has found the key to post-baby fashion -- solid undergarments.

The 39-year-old actress gave birth to son Alexander "Sasha" Pete less than three months ago and appeared at a Calvin Klein event in London earlier this week looking slim and toned.

She disclosed the secret to her post-baby fashion success to People magazine. "I've got a lot of solid undergarments," she joked.

"Good classic lines can also help cheer up an out of shape body," she said.

Other than the slight modification to her wardrobe, the actress is enjoying motherhood so far and says that it may be "hard work" but that she just loves it!