It will go into public circulation on 2 November 2011 and it will be the first time two portraits have appeared on the reverse side of a note.
It incorporates a range of new and tougher security features, although the Bank of England is remaining silent about their exact nature.
When the new £20 note was released it had at least eight security features on it -including ultra-violet features, holographic strips and a see-through register that took the shape of a pound sterling symbol when held up to the light .
Boulton and Watt were a pioneering force during the industrial age, and formed a business partnership that gave Britain the edge with their commercial steam engine designs.
The pair are depicted along with the Whitbread Steam Engine and Matthew Boulton’s Soho Manufactory.
Quotes from iconic pair have been included under their names, too. Matthew Bolton is attributed with the words: “I see here, Sir, what all the world desires to have: POWER.”
His counterpart, the engineering side of the partnership, has the words “I can think of nothing else but this machine.”
The note will replace the existing version which features Sir John Houblon, the first governor of the Bank of England, and which has been in circulation since 1994. There are almost £10bn worth of them and their withdrawal date has yet to be announced.