The event invite confirmed that we'd see "the next smartphone from Motorola" and teased that it's "made to last. Priced for all."
This will be the first handset to come out of Motorola since it was sold by Google to Chinese firm Lenovo - although the Moto E isn't 100% nailed on to be the phone on show.
Other rumors suggest Motorola is working on the Moto X+1, an updated to the mid to high-end Moto X, which could potentially break cover at the London event. More recently we've even heard about new versions of the Moto G and a handset going by the moniker Moto G Cinema.
TechRadar will be reporting live from the launch on May 13 to bring you all the latest as it happens.
Moto E price
As we've already mentioned, the invite to Motorola's May 13 event teases that its new smartphone will be "priced for all" - a potential hint that the handset will come with a super low price tag.
Going by the rumored specs for the Moto E - you can find these out further on - we're expecting it to sport a price tag which comes in below the Moto G.
Considering you can pick up the 8GB G for around £100, $180 (around AU$180) SIM-free we reckon the Moto E may fall into the £50-£70 (around $130, AU$110) bracket.
Moto E display
As you'd expect, the display on the Moto E isn't being touted as anything fantastical, with a 4.3-inch size appearing to be the popular consensus among leakers.
That would make sense, as it's a touch smaller than the 4.5-inch Moto G - but it may stick to the same 1280 x 720 resolution.
If that's the case then the Moto E would have a sharper screen than the G, although we wouldn't be surprised if Motorola went with a 800 x 480 resolution - the same as the 4-inch Nokia Lumia 520.
Moto E power and OS
One of the attractive points about the Moto G was its 1.2GHz quad-core Snapdragon 400 processor, giving the handset a decent amount of grunt under the hood.
Unfortunately it looks like the Moto E may have to make do with a dual-core offering, as several different leaks have all quoted a 1.2GHz dual-core chip.
That processor will apparently be backed up with 1GB of RAM which should ensure that Android 4.4.2 KitKat runs smoothly on the Moto E.
Going by the operating system on the Moto X and G, Motorola is unlikely to tinker with Android too much. That means you'll get an almost stock version of Google's mobile platform, with a handful of additional features thrown in.
Moto E camera
The Moto E is said to inherit the same 5MP camera that you find on the Moto G, but round the front there's no good news.
It appears that Motorola has chosen not to include a front facing snapper on the Moto E which may deter the young, selfie-obsessed market.
Moto E battery and connectivity
With a potentially smaller screen and less powerful processor inside the Moto E we should be able to expect at least half decent battery life from the handset.
A spec list leaked by a Brazilian network lists the Moto E as sporting a 1900mAh battery. That's slightly smaller than the 2070mAh power pack in the Moto G, but larger than the 1450mAh offering in the Lumia 520.
In terms of connectivity don't go expecting 4G capabilities on the Moto E, as the phone is more than likely set to arrive in a 3G variant. This has been backed up by multiple rumors, but Wi-Fi, GPS and Bluetooth will all feature.
Apparently you'll get just 4GB of internal storage, which is pretty poor, but a microSD slot is said to be housed beneath the removable rear cover allowing you to build on that paltry offering by up to 32GB.
Moto E design
A variety of leaked shots claiming to show the Motorola Moto E in all its glory have hit the web, and if they are accurate then you can expect it to look similar to the Moto G.
It also looks like you'll be able to pick it up in a variety of colors with black, white, yellow and teal hues all appearing online via the reliable @evleaks.
While the Moto G had a speaker on the rear of the device, it looks like the Moto E may have its internal speaker on the front, just below the screen.
Front facing speakers are becoming more popular on our mobiles with the likes of the HTC One, One M8 and Sony Xperia Z2 all adopting in-your-face placements.
One site lists the Moto E as having an extremely slender 6.2mm profile, which would make it one of the slimmest handsets on the market.
We find this hard to believe considering the Moto G had a rather slightly bulky 11.6mm girth.