Kelsi Willow Nielsen is a supporting character in the High School Musical movies. She is a pianist at East High.
Kelsi Nielson is considered, by some, to be a minor character in the High School Musical series. Her role in the movies, however, have been an important factor in moving many parts of the plot forward. Kelsi composed the musical Twinkle Towne in her junior year at East High School. This musical included several songs that were not in the movie, but the ones that appeared in the film were What I've Been Looking For and Breaking Free.
She got a summer job at Lava Springs Country Club, which Sharpay's family owned. After Sharpay Evans stole You Are the Music in Me (which she made Kelsi "transpose" into her key), Kelsi decided to get her payback and wrote Everyday. She is best friends with Taylor McKessie, Gabriella Montez, and Martha Cox. Her love interest in the first two films was Jason Cross, but changes to Ryan Evans for the final third installment.
She was accepted to the Julliard School for its scholarship along with Ryan because of her music in the Senior Year Spring Musical.
Unlike the main female characters, Kelsi's love-life is mostly ambiguous, and almost entirely implied. As Kelsi did not have an established love interest in the first movie (her relationship with Jason was implied during the finale, but not before), several pairings have struggled for dominance in fanfiction, fanvids, and other media.
Ryelsi/Relsi (Ryan and Kelsi)
Relsi/Ryelsi is a pairing of High School Musical 3: Senior Year.
In the first movie, Ryan shows indifference to Kelsi, but they sit at the same table in the cafeteria (as shown just before Stick to the Status Quo).
In High School Musical 2, however, Kelsi is shown to have a locker next to Ryan's. In addition, Ryan and Kelsi actually speak to each other during the movies, and they work together off-screen to plan the Wildcats' routine in the talent show.
Ryelsi gains support in High School Musical 3. They sing a duet together (along with Troy and Gabriella) called Just Want To Be With You, after Sharpay orders Ryan to take Kelsi to prom in order to steal "Just Want To Be With You".
Jelsi (Jason and Kelsi)
Jelsi is the official pairing of the first two movies. It has the most evidence in its favor, at least for the first two movies.
During the end of High School Musical, Kelsi receives a basketball from Troy. Jason walks up to her, takes her hat off and tosses it off-camera, and helps her shoot a basket. Jason is also pictured with Kelsi at the end of High School Musical 2, when the characters are coupled and holding lanterns (Troy with Gabriella, Taylor with Chad, and so on). However, Kelsi and Jason almost never speak to each other directly.
Jacksi/Jelsi (Jack and Kelsi)
- In a minor stage version of the production, the role of Kelsi was portrayed by Amy W. and Keeley A.