The new-look bottle, which The Greene King Brewing Company will launch in mid-September, retains the octagon-shaped MG badge label, but will also have a neck label.
The company will be replacing all 330ml bottles with a 355ml format, which will have a retail price of £1.59. However, most are likely to be sold in packs of 18. These will join 500ml and new 750ml bottles, priced at £1.75-£1.82 and £2.19-£2.35 respectively.
Take home and export director Neil Jardine said: "We have taken a 'handle with care' approach in updating the image of Old Speckled Hen and creating a design that appeals to both current and target drinkers."
The company has grown Old Speckled Hen by nearly 60% since it acquired it in 2001, according to Jardine. While it is a £20m brand, he said the company couldn't afford to rest on its laurels. "We're taking a great product and making it better. We are looking to double our business on Old Speckled Hen in the next two years."
The ale was first brewed in Abingdon in Oxforshire in 1979 to commemorate the 50th anniversary of the MG car factory. It was named after a paint-spattered car known as the "owd speckled 'un", which became Old Speckled Hen over time.
The new bottles will be supported by print advertising as part of a £1m spend.