Christina Applegate Christina Applegate

Christina Applegate is People's Most Beautiful Star of 2009.

Joining the Samantha Who? star in this year's Top 5 are Halle Berry, the female stars of 90210, Ciara, and Zac Efron. Also making the list are Dancing with the Stars' Julianne Hough (No. 9), Michelle Obama (No. 12), Kristen Wiig (No. 16) and Angelina Jolie (No. 17).

Applegate — who underwent a double mastectomy after being diagnosed with breast cancer last summer — shared her approach to overcoming obstacles. "You have to get through the physical transformations, then buck up, go to work, and try to be the normal, happy Christina for everyone around you," she told the magazine.

The actress, 37, described how she's matured. "I used to be really shy but I started to come into my own in my late 20s and early 30s," she said. "Now I'm not afraid to speak up in a room full of people and be a part of the conversation."

Applegate also credits her boyfriend, former Porno for Pyros bassist Martyn Lenoble, with helping her through her cancer battle and making her feel "beautiful" about her body.

"I'm very grateful to Martyn for coming along at a time that he did because he's been my rock through all of this," she said. "He gave me something to really want to live for and something to smile about."

Follow TV Guide on Twitter for breaking news and scoop.