Ernest was the fifth son and eighth child of Queen Charlotte and King George III of the United Kingdom, Frederica's paternal aunt and her husband.

Frederica was born in the Altes Palais of Hanover as the fifth daughter of Charles II, Duke of Mecklenburg-Strelitz, and Princess Friederike of Hesse-Darmstadt.

Maria Louise's choice of a Swiss teacher for the girls, Salomé de Gélieu, proved to be a good one.

Queen Frederika Louisa of Hesse-Darmstadt, wife of King Frederick William II, was a first cousin of Frederica's mother.

On 14 March 1793, the Mecklenburg-Strelitz duchesses "coincidentally" met King Frederick William II of Prussia at the Prussian Theatre in Frankfurt-am-Main.

[1] The double engagement was celebrated in Darmstadt on 24 April 1793, only a few weeks after the sisters fortuitously met their future father-in-law at the theatre.

The prince recognized his paternity and requested her hand in marriage, a proposal that was quickly granted in order to avoid scandal.

Frederica had to maintain her family with her own resources after her former brother-in-law Frederick William III refused to restore her annual pension as a dowager princess of Prussia.

William Christian, Prince of Solms-Braunfels, Frederica's brother-in-law and head of the family, advised her to get a divorce, with his full approval.

All parties agreed, including the Prince of Solms-Braunfels, but Frederick William's sudden death on 13 April 1814 precluded the need for a divorce.

During her marriage to Ernest she gave birth three times, but only a son survived, who would eventually become King George V of Hanover.

[1] The Court master builder Georg Ludwig Friedrich Laves was instructed by the King to build a mausoleum for his wife and himself in the garden of the chapel at Herrenhausen Palace.