Irene Frances Adza Mountbatten, Marchioness of Carisbrooke, GBE, DStJ (née Denison) was born in London, England, the daughter of William Francis Henry Denison, 2nd Earl of Londesborough and Lady Grace Adelaide (née Fane).

She married Alexander, 1st Marquess of Carisbrooke, son of Prince Henry of Battenberg and Princess Beatrice of the United Kingdom, on 19 July 1917 at St. James's Palace, Chapel Royal, St. James's, London. From the day of her marriage, her married name became Mountbatten, and she was styled as the Marchioness of Carisbrooke.

She was invested as a Dame Grand Cross of the Order of the British Empire (GBE) and invested as a Dame of Justice of the Order of St John of Jerusalem (DStJ). In Spain, she was invested as a Dame of the Order of Queen Maria Luisa.

She succeeded Princess Henry of Battenberg as President of the Frank James Memorial Hospital at East Cowes in 1946, carrying on the role until it was taken over by the National Health Service in 1948.

She died on 16 July 1956, aged 66, in London. Her ashes were interred at St. Mildred's Church, Whippingham, Isle of Wight.