The UK's departure from the European Union in 2021 has jeopardised most European players' prospects of playing county cricket without taking up an overseas spot, but de Leede qualifies as a local. He played for MCC Young Cricketers in 2019 and is understood to have pre-settled status in the UK.
"At only 23, Bas has established himself on the international stage with performances in the recent T20 World Cup," North said. "He is a genuine allrounder and brings quality and a skillset which will strengthen our playing squad in the T20 Blast and will provide depth in our County Championship."
He is the second Netherlands player to follow Campbell to Durham after fast bowler Brandon Glover, who signed a two-year contract last month. The KNCB said in a statement that de Leede would still be available for the 2023 World Cup Qualifier in Zimbabwe in June-July.
"I am really excited to be joining Durham for the next two seasons," de Leede said. "I can't wait to move over to the UK and meet the rest of the players.
"To play county cricket has always been a dream for me and I will be forever grateful to Durham for giving me the opportunity to do so. I look forward to meeting the Durham fans and supporters somewhere along the boundary this season."