Who was a actor of a star of M1 's sequel
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:people.person .
?x0 ns:film.actor.film/ns:film.performance.character ?x1 .
?x1 ns:film.actor.film/ns:film.performance.film ?x2 .
?x2 ns:film.film.prequel M1
}