Casey Stoner, Ducati's only MotoGP champion, rode his first laps on a Desmosedici since 2010 during the start of a private test at Sepang today (Saturday).
The 30-year-old Australian - who won a second crown for Honda before retiring at the end of 2012, then participated in occasional HRC MotoGP tests and an ill-fated entry in the Suzuka 8 Hours - is returning to Ducati as a brand ambassador and test rider.
The first stage of that new role, which fans hope will extend to a possible wild-card race appearance some time this season, saw Stoner take to the Malaysian track shortly after 11am to start a series of short runs on last year's GP15.
There are currently no plans for Stoner to try the GP16, but there is a chance he will ride at some point during next week's official test (again with the GP15).
Stoner is testing alongside Ducati development rider Michele Pirro - who is shaking down the new GP16, to be used by factory racers Andrea Iannone and Andrea Dovizioso next week - with test riders from Yamaha and Honda also present.
MotoGP is switching from Bridgestone to Michelin tyres and adopting a single ECU system for 2016. Stoner's only season on Michelin tyres was his rookie 2006 MotoGP campaign, with LCR Honda.
The track is open until around 6pm, with Stoner and Pirro also testing tomorrow. The official MotoGP test attended by the 2016 race riders then starts on Monday morning.