Ojeda will make his solo Supercars debut at the Winton SuperSprint next weekend in a third WAU Holden.
That will be followed by a second outing in Darwin for the Triple Crown at Hidden Valley.
Ojeda has experience in Super2 and has two Bathurst 1000 starts to his name from the last two years.
He was linked to a Super2 deal with WAU for this season, however that ultimately didn't come to fruition.
Ojeda will sample the WAU Commodore for the first time at today's Winton test.
“I’m really excited to be joining Walkinshaw Andretti United this year," said Ojeda.
"It’s an incredible opportunity, and it will be awesome to be back behind the wheel again.
“Today’s test at Winton will be great, not only for the laps, but it’s really important in terms of getting to learn the WAU Supercar.
"In addition, it will be great to join both Nick [Percat] and Chaz [Mostert] and learn from two super experienced drivers.
"It will also be a great opportunity to bond with the team around me as well before we are racing in just over a week.
“Can’t wait for Winton first, but Darwin as well, to get out there, gain some experience, and hopefully get a few good results along the way.”
This is the second year WAU has run a wildcard programme, after Kurt Kostecki made a trio of starts in a third entry last year.
“It’s fantastic to have Jayden with us for two rounds as a wildcard, we all can’t wait to see him make his [solo] main game debut and show what he is capable of," said WAU team principal Bruce Stewart.
“There’s no doubt he is a great young talent of the sport, so giving guys like him the opportunity to showcase their skills in the main game is not only pleasing for us as a team, but also crucial for the sport.
“We are excited to see what Jayden can do with us, which will hopefully progress his career at the same time. It will be great to have him alongside Chaz and Nick, all starting next weekend."
Ojeda will be one of two wildcards in the field for Winton, with Jordan Boys making his solo Supercars debut in an Image Racing-run, Erebus-backed entry.
The Winton SuperSprint will take place on May 21-22.
