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Unstrung - Chanel Celaya and Sofia Mattsson cast

ABC Family's tennis drama Unstrung has filled two lead roles with two up-and-coming actresses.

Chanel Celaya and Sofia Mattsson have joined the one-hour pilot from Life Unexpected executive producer Emily Whitesell, The Hollywood Reporter has learned.

Unstrung explores the sexy, cutthroat and emotional stakes of the professional world tour of tennis as brother and sister Luke and Ellie Holt compete to move up the ranks. The Holts may seem to have it all in a world where success is not only determined by prowess on the court, but by looks, charm and the ability to hide your faults under pressure from fans, critics, opponents and even your closest allies. But a major family secret threatens to turn their lives, and their hard-earned family “brand,” upside down.

Celaya has landed the main role of Ellie, an athletic, spunky beauty with great talent but not-so-great discipline. As Luke's younger sister, she is ranked 50th in the world but could -- and should -- be ranked much higher, if she cared to focus more. A lover of junk food, Ellie has a tendency to romance other players and mouth off during interviews.

Mattsson has booked the part of Ninotchka Andropov, a diva ranked 3rd in the world but first in looks. Her boyfriend, Nicolai, is the son of a mobster and is also her manager, but she has grown wary of his gambling, jealousy and violence. Attracted to Luke, Ninotchka knows she must keep their burgeoning romance a secret from Nicolai or he could destroy her career.