The managing director of engineering firm JJA Consulting Group, Jinadasa has imported a 2007-build Gallardo LP520 from Germany, which he will race in the AGTC's Trophy Class.
The car contested 12 FIA GT3 Series races across the 2007 and 2008 seasons before being sold to a German collector.
Jinadasa had hoped to have the car in time for the start of the 2013 AGT season, but customs delays will see it debut at the upcoming Phillip Island event on May 24-26.
It is currently undergoing a complete rebuild ahead of the Victorian meeting.
Originally intending to step away from racing after winning the AGT's Challenge Class last year aboard his 997 GT3 Cup Car, Jinadasa admits that the plan didn't last long.
“I think when I made the decision to sell the Porsche, I thought I had made a sensible business decision, and I took the emotion out of it, but what I hadn't realised was that it was that emotion that kept driving me forward and allowed me live on the edge a little.
“I loved the Porsche, but I felt I'd gone about as far as I could with that car, whereas the Lamborghini is a completely different beast, so it will require more thought, more practice and more finesse. It will be a new project, and new projects are always fun.”
Roger Lago and Justin McMillan are both campaigning newer specification Gallardos in the Championship Class of this year's AGTC.
The title race is being led by reigning champion Klark Quinn (Porsche) after two of six rounds.