A new-style £50 note with enhanced security features will come into circulation in November, the Bank of England said today.
It will celebrate the renowned 18th century business partnership of entrepreneur Matthew Boulton and engineer James Watt.
The release will mark the first time two portraits have appeared together on the back of a Bank of England bank note.
A range of new security features have been incorporated into the design.
The Bank said it would release more details about this, along with a publicity and education campaign, when the new note is introduced on November 2.
Boulton was a leading entrepreneur of the Industrial Revolution.
On leaving school he worked in his father's buckle-making factory in Birmingham, which he later inherited.
He was particularly enthused by the development of steam engines and the minting of coins.
In 1775 Boulton went into partnership with Watt, whose improvements to steam engine design had led to greater efficiency and cheaper running costs.
The pair pioneered the use of the steam engine in the cotton spinning industry.
Boulton established the Soho Mint, which produced high-quality coinage using steam-driven machinery.
Watt was involved in several civil engineering projects during his life, including a survey and estimate in 1773 for a canal between Fort William and Inverness. The Caledonian Canal was constructed in the early 19th century.
The new bank note will also be the first in circulation to be signed by Chris Salmon, who was appointed the Bank's executive director, banking services and chief cashier in April.
It will initially circulate alongside the current £50 note featuring Sir John Houblon, the first Bank of England governor.
The Bank will make an announcement about the withdrawal of the Houblon note in due course.