From Wikipedia, the free encyclopedia. Olesya Yurivna Rulin (Russian: Oлeся Юрьевна Pулин; born March 17, 1986, height 5' (1,52 m)) is a Russian American actress. She is best known for co-starring in the first three films of the High School Musical franchise as Kelsi Nielsen. She also starred in the films Private Valentine: Blonde & Dangerous (2008) and Flying By (2009).