Hansen, originally from Germany, joins Fallon after 11 years at the neighbouring Minneapolis agency, while Sorensen is making a return having previously been a copywriter at Fallon between 1995 and 1999.
The two are best known for their award-winning campaigns for Porsche and Harley Davidson, which they created at Carmichael Lynch. They recently took the Harley Davidson "faces" campaign to a Cannes Lion award. Their work has been honoured by the MPA Kelly awards, the Clios, the One Show, Communications Arts and the Athenas.
During his time at Fallon, Sorensen has also worked on Miller Lite, Jim Beam brands, Lee Jeans and Time.
Prior to Carmichael Lynch, Hansen worked at Hunt Murray and Kaufman Stewart in Minneapolis, and Scholz & Friends in Hamburg, Germany.
Kerry Feuerman, creative director at Fallon, said: "It would be hard to find a better team of craftsmen than Hans and Eric. They know how to create a consistent voice and visual language that never strays."
Sorensen said: "It wasn't long ago that Fallon was considered unstoppable. The energy in this place right now is huge. It feels like it's about to take off again in a big way."
Hansen said: "Kerry's enthusiasm is infectious. It's very obvious where this place is headed."
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .