Stars were out and about on Monday, taking a break from their red carpet duties.  While many celebs opted for a more casual street look, leave it to Rihanna and Lady Gaga to get dressed to the nines as they performed their daily duties.  Who else dressed up, and who opted for UGGS?

Click here to see Rihanna, Lady Gaga, Brody Jenner, Paris, Bradley Cooper, Sienna Miller, Emily Blunt, Rumer Willis, Keifer Sutherland, and Jon Gosselin in their Monday best!