Rosberg was first to sample the F1 W06 Hybrid, with which the Silver Arrows will be aiming to defend the constructors' and drivers' championship double they secured in record-breaking fashion during the 2014 campaign.
The German then handed over to Hamilton, although the Briton's time in the car was cut short as a blizzard brought the day to a premature close. In total, the duo racked up 18 laps (47.2 kilometres) around Silverstone's national circuit.
The team released two photographs of the car, which features several noticeable changes including a different nose design and re-sculpted bodywork, particularly in front of the rear wheels.
Be sure to visit Formula1.com tomorrow for an exclusive feature on Mercedes' first day of running in 2015, including insight from the team's executive director (technical) Paddy Lowe.