"We've raced against Russell since the start of our careers in V8 Supercars and had some fantastic battles. It's great to have Russell as a part of the team rather than as part of our opposition. He is a hard but fair racer and a great asset."
Ingall was a surprise visitor at Winton Raceway last week for a scheduled Nissan test day.
The 52-year-old was sprung cutting laps in Kelly's V8 Altima, sparking speculation that the now Fox Sports commentator would return to the sport.
Kelly, also a co-owner of the Nissan team, said Ingall earned a drive following an impressive show of speed.
"Coming away from the most recent test day his ability was out there for everyone to see," Kelly said.
"His capability to adapt to the car and gel with the guys was quite remarkable, so from that point of view it leaves us very excited for the endurance races to come.
"The category keeps getting tougher and tougher, so the endurance season is a critical time in the championship. You need to have someone is your car that's rock solid, someone where you can sit back and know that they're going to do a great job.
"Russell is a very fierce racer and someone who will be very solid from that point of view.
"Russell will be a huge asset to the team in terms of driving and also in just talking to us about where we're at with the team at the moment."
Kelly is confident Ingall can help Nissan conquer the mountain for the first time since the beast named "Godzilla" reigned supreme in the early 1990s.
"Coming away from the test day he provided some excellent feedback and really helped us cement our strengths and weaknesses," Kelly said.
"That sort of feedback helps give us confidence about where we've come from and where we're going. When drivers first get into a car they do notice certain things and the more you drive the car the more you get used to it. So it's great to have someone of Russell's calibre come in and provide feedback. It's a very big positive for the team to have Russell on board for those two reasons: to help us with our endurance campaign and also to provide feedback on where we're at."
The championship series will resume in Perth from Friday at Barbagallo Raceway.