The three-minute live spot, created by 4Creative, airs at 8.10pm during 'Come Dine with Me' and will be shown in real time from the Madrid jump with no special effects, as aprt of the launch of Honda's new Accord model.
However, the stunt will be abandoned if the weather is poor and instead a rehearsal jump, filmed last night, will be broadcast.
The ad follows a series of five short teaser ads, which launched on May 12 and featured the skydivers preparing for a big event but carried no Honda branding.
The only clue to what the teaser ads were about was the web address www.difficultisworthdoing.com at the end of each clip, which linked to a blog about the making of the ad shot at The Perris Skydive Centre in California.
After the live ad tonight, the campaign will continue with the main Wieden & Kennedy-created TV ad, called "jump", which debuts on Sunday June 1. It was created by Tony Davidson and Kim Papworth of W&K.
"Jump" was filmed in the Mojave Desert, California, and features a large team of skydivers attempting to form shapes in the sky that hint at the new technologies on the Honda Accord including a suspension spring, a camera, a steering wheel and ultimately the word "Accord".
Part of the shoot involved high-speed divers reaching up to 300mph, meaning the cameraman had to curl up into a ball in order to fall faster than the skydiver.
Both ads are based on the wisdom of Honda's founder, Soichiro Honda, who once said "Difficult is worth doing".
Harry Cooklin, marketing communications manager of Honda, said: "The campaign has been difficult but it was definitely worth doing. We are always looking to move boundaries when it comes to our advertising, and so being involved in the UK's first truly live TV ad is perfect for us."