WATCH: 2020 Land Rover Defender test with the Red Cross

The 2020 Land Rover Defender has once again been teased ahead of its global debut ahead of the Frankfurt motor show this September.

This time a short video shows a late-stage camouflaged prototype driven on Dubai's sand dunes and the famous Jebel Jais highway with off-road experts from the Red Cross.

While testing at altitudes of 2000m, temperatures were said to have topped 40 degrees C, proving a true test of both the Defender's cooling system and climate control.

Set to be on sale at the end of this year in some global markets (early 2020 in Australia), much is already known about the iconic off-roader's return.

We know that it will be offered in both a three-door '90' version (in five-seat and six-seat configurations) and a longer '110' that will be capable of seating up to eight.

According to sources, the Defender will eventually be available in three body styles and four model grades, including Urban, Country, Adventure and Explorer versions.

Measuring in at 4323mm (170 inches) in length – up from less than four metres for the last Defender 90 -- the five-door Defender 110 will offer the choice of five, six or seven seats across three rows and measure 4758mm (187 inches) long.

Finally, reviving a Defender nameplate previously seen only on the dual-cab ute version will be the five-door Defender 130, offering up to eight seats and measuring a lengthy 5100mm (201 inches).

The Defender 90 and 110 are tipped to be available late this year or early next year, followed by the 130 about 12 months later. It’s unclear whether the model designations continue to refer to wheelbase lengths in inches.

The new Defender will be launched with conventional and 48-volt mild-hybrid versions of Jaguar Land Rover’s Ingenium range of petrol and diesel engines, followed by plug-in hybrid and, potentially, all-electric powertrains.

On the diesel side, according to rumours, there will be two versions powered by the firm’s 2.0-litre diesel – a D200 with 147kW and a D240 that produces 177kW -- plus a powerful D300 that musters 221kW from its 3.0-litre inline six-cylinder.

The D200 is expected to hit 100km/h in around 10 seconds, while the punchier D240 should take 8.3sec and the flagship D300 around 7.4sec.

Three petrol Defender engines will also be offered – a P300 (221kW), P400 (294kW) and the plug-in hybrid P400e that will produce up to 645Nm of torque and be capable of reaching the 100km/h in a very un-Defender-like 5.9 seconds.

It’s not known if the P300 and P400 will be powered by the car-maker’s inline six-cylinder petrol engines, or if the less powerful P300 will be powered by a mild-hybrid version of the 2.0-litre turbocharged four-cylinder that currently powers the sporty F-TYPE.

Aside from the D300 diesel, all engines are expected to be available from launch in 2020.

In the future, more powerful SVR, go-anywhere SVX and luxurious SVAutobiography variants could join the range.

As we know from a series of leaks, spy shots and official announcements — including images of pre-production vehicles — the new Defender will look more like the latest Discovery than the model it belatedly replaces and will wear a tailgate-mounted spare wheel and clamshell bonnet.

It was designed, developed and engineered in the UK but will be produced in JLR’s new plant in Nitra, Slovakia alongside the Discovery, with which it will share its D7u platform.

That means that unlike the original 1948 Land Rover, whose aluminium body was bolted to a steel ladder frame, the new Defender be an all-aluminium monocoque design.

Land Rover built more than two million examples of the outgoing Defender before production of the off-road icon ended after 67 years in 2016, but hopes to radically ramp up sales of the new model to a wider global audience.

Despite its unibody construction and mass-market appeal, JLR says the 2020 Defender will be the “most capable off-road Land Rover vehicle ever”.

It claims that, by the time it reaches production, prototypes will have completed more than 45,000 tests and millions of kilometres of testing from Death Valley to Dubai and the Nurburgring, including altitudes of more than 4000 metres and temperatures as low as -40 degrees and as high as +48 degrees.