07/12/2007 at 08:00 PM EDT
On just her second day of filming on the Grey's Anatomy
set this season, new cast member Chyler Leigh tells PEOPLE: "Everyone's happy to be back."
Leigh first joined the show in her role as Lexi Grey, Meredith Grey's half-sister and a Seattle Grace intern, for the third season's final two episodes, and found out two weeks ago that she was a new series regular.
"Everyone is super gung-ho about the season," she said Thursday. "[Show creator] Shonda [Rhimes] said in her blog this is going to be a different season. Last season was so dramatic, and everything came crashing down. This season will be the redemption from all that mayhem."
The show was rocked by the controversy over Isaiah Washington's use of a gay slur, ending with the actor's firing from the show
and parting comments
But Leigh, 25, says the experience of joining the hit show has been a series of pinch-me moments. "I'm still in every moment looking behind myself going: 'Who, me?' I still walk on and before every scene my heart starts pounding, but that's always been the case for me. I use it as a motivator."
Leigh, who is married to actor Nathan West and has two children with him, Noah, 3, and Taelyn, 10 months, has had several television roles to prepare her for the experience, including gigs on Reunion
and The Practice
"At first I had that kind of new kid in school feeling," she jokes. "But everyone has been warm and welcoming with lots of hugs and pats on the back. This whole experience has been wonderfully overwhelming. My biggest thing right now is just: Buckle up! I don't know what to expect."