The regiment was reconstituted as a hussar regiment in 1807 as the 15th (The King's) Regiment of (Light) Dragoons (Hussars). It landed at Corunna in November 1808 for service in the Peninsular War and defeated two regiments of French cavalry at the Battle of Sahagún in December 1808. At the battle two French lieutenant colonels were captured and the French 1st Provisional Chasseurs à cheval, who lost many men captured, ceased to exist as a viable regiment. However, the commanding officer of the 15th Hussars, Colonel Colquhoun Grant, was wounded in the battle. The regiment embarked at Corunna for their journey home in January 1809.