The in-form 26-year-old has signed a pre-contract agreement with The Terrors, with a club-held option of a further 12 months beyond 2028.
Rose is equal-third in the golden boot race with eight goals from 21 games, behind Auckland duo Sam Cosgrove (10) and future teammate Jesse Randall (nine), the New Zealander also signing a pre-contract deal at Tannadice in January.
Rose will link with six-cap Socceroos defender Ryan Strain, former Western Sydney Wanderers striker Zac Sapsford and England-born goalkeeper Ashley Maynard-Brewer as the fourth Australian contracted to United.
Rose is enjoying his most productive seasons at the Jets after signing from Macarthur FC in 2024, matching the goal tally he set last season with five rounds remaining before the ALM finals.
"While we are disappointed to lose Lachie, we are delighted for him that he has earned this opportunity to test himself in Europe," Newcastle's football manager Nigel Boogard said.
"Opportunities like this are what we want for our players and Lachie has put himself in this position through his work and commitment."
Rose has scored 16 goals in 39 games for Newcastle, currently perched one point above Auckland FC, and become something of a cult hero among Novocastrians by helping place the Jets on the cusp of a maiden premiership, having finished runners-up in 2008 and 2018.
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