The International's Naomi Watts made an appearance on the Late Show last night - just two months after giving birth to her second son - and girlfriend is tired.

Soon after sitting down and giving the audience a glimpse of her ample, new-mom cleavage, Letterman launched into a discussion about babies, giving Naomi the opportunity to school those who don't know just how exhausting new motherhood can be, which we can summarize into the following three words: Breastfeeding, Brainpower, Bed.