First announced in June, the newwill drop later this week.
An update to Apple's website on Tuesday delivered the release date: Dec. 14.
With the iMac Pro, Apple is targeting professionals who need really fast processing and lots of computing horsepower.
"Pros love iMac," Apple says on its iMac Pro page. "So when they asked us to build them a killer iMac, we went all in. And then we went way, way beyond, creating an iMac packed with the most staggeringly powerful collection of workstation-class graphics, processors, storage, memory and I/O of any Mac ever."
Specifically, the $4,999 all-in-one desktop computer will feature a pro-level Intel Xeon processor, up to 18 cores and AMD's Radeon Vega graphics. It'll have 128GB of RAM and up to 4TB of SSD storage.
Apple hasn't given its Macs as much attention in recent years as its other devices like the iPhone and Apple Watch, and its desktops in particular have been overdue for an update. In late 2016, the company did update its MacBook Pro laptop, a revamp four years in the making.
An Apple spokesman said the company will offer more details about the new iMac Pro on Thursday.
UK and Australian prices have yet to be announced. It's available the same day in the UK and Dec. 15 in Australia.
Read our first take here:
First published Dec. 12 at 6:38 a.m. PT.
Update at 8:17 a.m. PT: Added Apple spokesman's response.
Batteries Not Included: The CNET team reminds us why tech is cool.
Does the Mac still matter? Apple execs explain why the MacBook Pro was over four years in the making, and why we should care.