London - Red Bull unveiled its first Honda-powered Formula One car on Wednesday with Max Verstappen driving the initial laps at Silverstone.
The team published images of the RB15 online with what it said was a temporary livery for filming before testing starts in Spain on Monday.
The former champions finished third overall last season, winning four races and well ahead of fourth-placed rival Renault.
Red Bull parted company with engine partner Renault at the end of 2018, switching instead to Honda, which also provides power units for sister team Toro Rosso.
Verstappen, who shared the victories with Australian Daniel Ricciardo last season, has a new team-mate for 2019 in Frenchman Pierre Gasly.