Scarlett Johansson shares son Cosmo's 'fun discoveries' about 'feet'

American actor Scarlett Johansson is gushing over her newborn son.

Speaking on PEOPLE (The TV Show!) Thursday, the 37-year-old actor star revealed that her tot Cosmo is making 'fun discoveries' these days involving his 'feet'. Scarlett shares Cosmo with husband Colin Jost.

"It's the best," she says, teasing, "I mean, feet, who knew? There they are. Life-changing."

The Black Widow actress added that Cosmo does "everything" when it comes to his tiny toes, sharing that he'll "stare at them, pull on them, chew on them."

"It's just unbelievable," she continues. "I mean, can you imagine you never realized you had feet and then you looked down and there they are? You're like, 'Whoa.' "

Scarlett welcomed Cosmo with husband Colin Jost in August. The actor is also mother to seven-year-old daughter Rose Dorothy.