German defence firm, Rheinmetall, will open a factory in the UK to produce barrels for artillery guns, as part of a new defence pact signed on Wednesday.
Under the so-called Trinity House Agreement, Berlin and London are seeking to deepen European security ties, notably in light of the war in Ukraine.
The factory, whose location is yet to be decided, will start producing artillery gun barrels in 2027.
These will be used for 120mm guns and 155mm howitzers, as well as for the British Challenger 3 tank.
The Ministry of Defence (MOD) said the new site will support more than 400 jobs and bring nearly £500m (€601m) to the British economy.
Sheffield Forgemasters, a supplier in northern England, will provide the plant with steel.
The opening of the Rheinmetall factory will also mark the first time that the UK has manufactured artillery gun barrels in 10 years.
Collaboration across domains
"The signing of the Trinity House Agreement marks a fundamental shift in the UK's relations with Germany and for European security," said the MOD.
"The deal will see the UK and Germany work together systemically for years to come on a range of ground-breaking defence projects and across all domains (air, land, sea, space and cyber)."
As well as the opening of the new factory, the countries will also work together to develop long-range strike weapons and drones.
There will additionally be collaboration on Boxer armoured vehicles, joint exercises will be held along Nato's eastern flank, and German P8 aircraft will periodically operate out of Lossiemouth in Scotland to help protect the North Atlantic.
Working together to protect underwater infrastructure on the seabed of the North Sea is also a priority.
Resetting European relations
The treaty marks an attempt from the UK's Labour government to reset relations with its European neighbours post-Brexit.
Germany and the UK are currently the second and third largest military donors to Ukraine, after the US.
European solidarity has become an increasingly pressing issue ahead of the US election, which could throw Washington's support for Ukraine into jeopardy.
The UK already has a defence pact with France, although this is its first with Germany.