Pippa Mann will make her second Indianapolis 500 start next month after securing a drive with Dale Coyne Racing.
The 29-year-old Briton announced on Tuesday that she will drive a third car for the team alongside Justin Wilson and Ana Beatriz.
"I actually first met Dale several years ago, before I came to the US, at what turned out to be the final Champ Car test at Sebring right before the open-wheel merger," she said.
"We've sort of had an ongoing conversation ever since then, and I actually got very close to getting in one of Dale's cars on Bump Day last year.
"A year later, we've now put this programme together."
Mann finished 20th in her Indy 500 debut with Conquest in 2011 and made the only other official IndyCar start of her career later that year when she was classified 22nd at Kentucky Speedway with Rahal Letterman.
She also participated in the Las Vegas race cancelled due to Dan Wheldon's fatal accident, and suffered burns in the multi-car crash.
Mann has been without a full-time drive since finishing fifth in her second season of Indy Lights in 2010. Her last single-seater outing was at Sonoma in Auto GP last year.
Her addition to the grid brings the confirmed Indy 500 field to 30, three short of the traditional car count of 33, although several drivers including Townsend Bell, Jay Howard and Jacques Lazier are all reportedly working on deals.