I've expanded it a bit...
Prince George gorged himself to death shortly before the advent of the initial Regency Crisis, say roughly around 1786. Prince Frederick, Duke of York and Albany (b. 1763) succeeds his brother as the heir apparent; but the untimely death of the Prince of Wales, his eldest son and heir, leads to a sudden deterioration in George III's already somewhat tenuous grip on sanity, leaving him in a similar state as in OTL 1811.
In Parliament, Charles James Fox (Whig) and William Pitt (Tory) clashed over provisions for a regency. William Pitt defended the royal prerogative, and Prince Frederick’s right, as Regent, to exercise the powers normally associated with the monarch. Charles J. Fox headed a faction advocating a more moderate 'regency council', subject to the consent of parliament, and operating within parameters set out by parliament. Fox was happy to stand up for parliamentary power and supremacy, whilst Pitt’s defense of Prince Frederick and the royal prerogative somewhat undermined his parliamentary support.
After much parliamentary debate, late 1787 saw the Regency Bill passed by the Commons. It created a regency council composed of Frederick, the Prince Regent; the Lord Privy Seal; Lord President of the Council; and one figure nominated by Parliament. The council required at least a majority of three members of the council (one of which had to be the Prince Regent) in exercising all aspects of the Royal Prerogative, except for the dissolution of parliament, calling of elections, and creation of peers. Queen Charlotte would be responsible for the royal household and the king’s person.
The First Regency Council (178

:
-Prince Frederick, Duke of York and Albany (Prince Regent)
-Charles Pratt, 1st Earl Camden (Lord President of the Council, 1784-94)
-Granville Leveson-Gower, 1st Marquess of Stafford (Lord Privy Seal, 1784-94)
-William Petty, 2nd Earl of Shelburne (Former Prime Minister, Irish Peer)