And it's hard to believe Julia Roberts' son is so grown up now! On Monday, the Pretty Woman star's husband Danny Moder took to Instagram to post a video of Phinnaeus, who is now - get ready for it - 20 years old! Wild, right?! Where did the time go?! Related: Liam Neeson & Son Daniel Show Support For Pamela Anderson In The SWEETEST Way! In the clip, which is set to the track Good Times Roll by The Cars, Phinnaeus can be seen showing off his impressive moves on a skateboard while wearing only a pair of navy blue pants and matching Vans.