Today is Jennifer Aniston's 40th birthday and she started the morning getting to work at a photo shoot. Over the weekend she hosted a big star-studded bash at her newly finished home and she has more to look forward to including the extra special song John Mayer wrote for her. We're celebrating Jen's big day with a look back at her nearly 20 years in show business — hopefully she has a fantastic time today filled with love from her nearest and dearest. Happy Birthday!

X17 Online