After landing her breakout role as Rachel Green on Friends, Jennifer Aniston took the lead as America’s sweetheart. The ELLE cover girl has starred in a slew of big-screen hits and graced countless best-dressed lists. While she’s known for her classic little black dresses, Jen knows what works for her and has always wowed on the red carpet with form fitting silhouettes and sexy heels. Clearly, her style is only getting better with age. Below, Jen’s best looks in honor of her 51st birthday.