Bosses said the deal will help accelerate Huel’s growth ambitions and drive its international expansion.
The companies have not disclosed the value of the deal but the Financial Times reported that it values the British business at around one billion euros (£870 million).
It is subject to closing conditions including regulatory approval.
Hertfordshire-based Huel was founded by Julian Hearn in 2015 to provide nutritionally complete food products, aimed at reducing meal times and providing essential nutrients.
The brand has rapidly grown in the years since, expanding into retail stores and growing its product range to items including powders, snack bars and drinks.
The deal comes amid efforts by Danone to expand further in the “functional nutrition” sector.
Danone chief executive Antoine de Saint-Affrique said: “We are delighted to welcome Huel and the Huel team into the Danone family.
“What they have achieved in the fast-growing complete nutrition space fully resonates with Danone’s mission of delivering health through food.
“Combining their range and best-in-class digital capabilities with Danone’s global reach and deep nutritional expertise offers exciting opportunities into the new and fast-growing nutritionally complete space, in line with our renew Danone strategy.”
Huel chief executive James McMaster said: “We’ve grown into an omnichannel business with a strong direct-to-consumer foundation, an expanding international footprint and a retail business that’s scaling quickly.
“With Danone, we will now have the infrastructure, distribution and R&D capability to go further, into new markets and to more people, as demand for convenient, complete nutrition continues to grow.
“We’re so proud of what the team has built and excited about what comes next.”