So what do you need to know about them? Read on and we'll reveal all.
1 They're different sizes
As their names suggest, the freshly unwrapped Nexus phones are different sizes.
The Nexus 6P is the flagship and is the follow-up to last year's Nexus 6.
It's actually slightly smaller than its forebear, but has a 5.7-inch screen which many would argue is quite big enough.
The Nexus 5X is its little brother, with a 5.2-inch screen. Again, it's the sequel to the two-year-old Nexus 5.
The letters after the names haven't been explained. Presumably they're to help punters differentiate between the new models and the previous Nexus 5 and Nexus 6.
Though could Google's new parent company's name Alphabet have anything to do with the letters?
2 The Nexus 6P is higher-end
As well as being bigger, the Nexus 6P has more impressive specs.
The screen resolution is 2,560x1,440 pixels (aka QHD or Quad HD), which is up there with the best smartphones around.
That gives it a pixel per inch count of 518ppi, which makes the iPhone 6S Plus's 401ppi look pretty small-fry.
It also sports a 12.3-megapixel rear camera and an 8-megapixel front-facer.
Inside is a Qualcomm Snapdragon 810 chip along with 3GB of RAM. Which should make it an absolute powerhouse.
Storage-wise, you can choose from 32GB, 64GB or 128GB.
3 The Nexus 5X is more modest. Think: mid-range
The screen resolution is lower (1,920x1,080 pixels), and so is the pixel-per-inch count (423ppi). It has the same 12.3-megapixel camera with laser-assisted autofocus and 4K video recording as the 6P, but the front-facer has been downgraded to 5 megapixels.
It also has less grunt: a Qualcomm Snapdragon 808 chip with 2GB of RAM. And less storage: 16GB or 32GB.
Both phones have fingerprint scanners and fast charging tech: Google claims a 10-minute charge gives the Nexus 5X almost four hours of battery life, while the same charge gives the 6P seven hours.
4 They're made by different manufacturers
Google usually contracts out its Nexus tablet and smartphone to different manufacturers, but this year it kept the production of the Pixel C tablet in-house. Instead, it farmed out each phone to different mobile makers.
The Nexus 5X is made by LG, who made the original Nexus 5. The 6P is made by Huawei – it's the first time Huawei has made a Nexus device. The original Nexus 6 was made by Motorola.
5 They're the first phones to run Android Marshmallow
Both run Android 6.0 Marshmallow out of the box. Buy one, and you'll get Google's new OS months ahead of other Android users.