Black swan's little duckling came out to play!

Natalie Portman and fiance Benjamin Millepied took their son Aleph, 4 months, out for a stroll and dinner in Geneva, Switzerland on Wednesday -- and only Us Weekly has the exclusive photos.

In one pic, Portman, 30, beams as her little guy chats at the dinner table. In another, French-born dancer-choreographer Millepied carries Aleph in a baby Bjorn on his chest as he holds hands with his bride-to-be during a romantic walk. See more pictures of baby Aleph.

The family is in Geneva as Millepied, 33, does choreography work for the National Geneva Theater.

The couple met and fell in love on the set of Black Swan, in which Portman starred; Millepied served as choreographer and also had a small onscreen role.

"It was seductive to watch them," a set source told Us of the pair. "There was no way the attraction could be missed. I don't think he could help himself -- she's dazzling!"

Little Aleph takes his name from the first letter of the Hebrew alphabet; the term also represents the "oneness of God" and the element of air.

Portman was born in Jerusalem and has dual American-Israeli citizenship.