The 'Drinking Buddies' star took to Twitter today (24.04.14) to announce that her one-day-old son Otis Alexander, whom she shares with her fiancé Jason Sudeikis, has urinated on himself already.
She wrote: "Having an infant son alerts me to the fact that every man, at one point, has peed on his own face. #awesome (sic)".
The 30-year-old beauty announced the birth of Otis, who was due on May 4, on Twitter yesterday (23.04.14) after welcoming him into the world two weeks early.
She tweeted: "Ladies and gentlemen, Otis Alexander Sudeikis has LEFT the building! (I'm the building). (sic)".
She also shared a black and white image of herself cuddling the newborn in a blanket.
The brunette beauty, who got engaged to Jason in January 2013, recently gushed about the bond she had formed with her son while pregnant.
She said: "He's moving around in there and no one else can tell - it's a little secret friendship."
The 'Rush' star also spoke about embracing her changing body during her pregnancy.
She said: "I just thought, Oh I'm going to hide this forever. But I ended up getting kind of excited to show the bump, as a badge of pride. Like, I'm a woman! Look at me making a human! I am a goddess!"
Olivia was previously married to Italian prince Tao Ruspoli for eight years until 2011.