Jose Maria Lopez will join the Young Driver Aston Martin team for this weekend's World GT1 finale in Argentina to support Tomas Enge and Darren Turner's title bid.
Enge and Turner are the only men who can still catch Vitaphone Maserati's Andrea Bertolini and Michael Bartels in the race for the series' first world crown. The Aston duo are 28 points behind with 33 available (25 from the championship race and eight from the qualification race) at San Luis.
Lopez will replace Christoffer Nygaard alongside Stefan Mucke in Young Driver's #8 entry.
"We are fighting for the world championship in Argentina," team boss Hardy Fischer explained. "Darren and Tomas are the only two drivers who can challenge the championship leaders and we also aim for the second place in the team championship.
"The track is new to most of the teams and drivers, so we decided to take advantage of having one local driver with track knowledge in the team.
"It was a tough decision to change the drivers for the last round, but with this championship being so tight and having so limited practice time, we think it will be an advantage for our entire team to have someone with a good track knowledge on board.
"Jose Maria knows the track from the FIA GT Championship in 2008 and on the personal side, he worked with our engineer Johannes Gruber in the past."
Lopez contested several FIA GT rounds with the ACA Argentina Ferrari project in '08, including his home event, where he charged from last to third before losing time in the pits. The 27-year-old Argentinean is a former Renault Formula 1 test driver and GP2 race-winner, and had signed for the US F1 team this year before the project collapsed.
Since leaving the European single-seater scene, Lopez has primarily raced in Argentina's TC2000 touring car series, in which he has become a double champion.
Fischer added that while Vitaphone remained an overwhelming championship favourite, his team would not give up until the title was mathematically settled.
"We remain optimistic and will give out best," he said. "Darren and Tomas have a tough job to do, but you never know what will happen. In the team championship, our goal now is to finish our first season in GT1 racing in the runner-up spot."