When he was ten years old, his father was deposed by the Coup of 1809 and the family was forced into exile. The Gustavian party tried to get him accepted as crown prince in 1809 and 1810, but were unsuccessful. Queen Charlotte, wife of the new king, was one of the leading figures of the Gustavian Party, and often visited ex-queen Frederica in her house arrest and worked for prince Gustav to be acknowledged as heir to the throne. She wrote of this issue in her diaries: during a dinner, General Georg Adlersparre told her that Jean Baptiste Bernadotte had asked whether she had any issue, and was interested when he found she had not. She said that the throne already had an heir in the deposed King's son. Adlersparre became upset and expressed the opinion of his party that none of the instigators of the coup would accept this as they feared that the boy would take revenge against them when he became King, and that they would go as far as take up the old rumour that the deposed King was, in fact, illegitimate and the son of Queen Sophia Magdalena and Count Adolf Fredrik Munck af Fulkila to prevent this.