By Josephine Cusumano
Updated Nov 24, 2015 @ 7:15 am
Katherine Heigl Birthday Lead
Credit: Time Life Pictures/Getty Images; Jason Merritt/Getty Images

Happy 37th birthday, Katherine Heigl! We're honoring the actress, who stole our hearts in Grey's Anatomy as Dr. Izzie Stevens, and her big day by looking back at her glamorous transformation from a high school cello player to one of Hollywood's biggest stars.

Who could forget how the Washington D.C.–born star got her start in Hollywood thanks to Disney's 1996 TV film, Wish Upon a Star? From that moment on, Heigl continued to score roles in TV movies and shows including the sci-fi series, Roswell, in 1999. It wasn't until 2005 when she starred on Grey's that she captivated viewers with her heartbreaking storyline with patient Denny.

What came next were leading roles in films including 27 Dresses, Knocked Up, Life as We Know It, and another television role in the now-defunct show State of Affairs. Aside from her acting career, Heigl is first and foremost a doting mother to daughters Naleigh and Adelaide, whom she shares with husband, musician Josh Kelley.

With a role in the upcoming CBS legal drama, Doubt, starring opposite of The Good Wife's Steven Pasquale and Orange Is the New Black's Laverne Cox, it looks like Heigl has a lot to celebrate in her 37th year. Take a look back at Heigl's transformation in honor of her birthday.