understudy
verb (used with object)
to learn (a role) in order to replace the regular actor or actress when necessary.
Used to describe actions that started in the past and continue into or have direct relevance to the present.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
There was one pale curate who looked as though he might have understudied Penley in The Private Secretary.
From Forty Years of 'Spy' by Leslie Ward