I can think of one major case where this effectively happened, but it wasn't exactly intended. In the English Glorious Revolution of 1688, William of Orange, the Dutch Stadtholder (their elected leader), was invited by English notables to invade and usurp his father-in-law James II.

James II was hated in Protestant Anglican England because he was a Catholic, but public ire was intensified when he proclaimed a Declaration of Indulgence which granted some religious freedom to Catholics and non-Anglican Protestant groups. When seven Anglican bishops refused to promulgate this Declaration, James had them detained and put them on trial for sedition; the bishops became heroes; James became a tyrant.

William of Orange was a Protestant monarch, and therefore a suitable replacement for James II in some ways, but crucially he was married to James' eldest Protestant heir, Mary. Before he was king James had already exposed himself as a Catholic and become a public enemy, and so his brother Charles II had prudently insisted on the raising of his children as Protestants, and arranged Mary's marriage to William.

Marrying Mary so that he might one day rule England was surely never part of William's intentions, but the marriage was essential in legitimising the Glorious Revolution and his rule. William II and Mary II were officially co-rulers, and while William was a pragmatic, desirable candidate for monarch, Mary's equal rule in her own right was crucial to their claim.