The vehicle had tinted windows and onlookers were unable to see if there were any rear seat passengers.
A source at the Royal wedding reception told the UK's Daily Express that William's best man speech had been 'naughty' and 'moving'.
'William managed to strike the right balance between hilarious and solemn,' the source said.
'He did mention their late mother, Princess Diana, and said she would have been proud of her younger son.
'He said he was proud of Harry too and welcomed Meghan as the sister he never had.'
Reports revealed guests celebrated the couple tying the knot by downing themed cocktails, eating up-market fast food, watching a spectacular fireworks display and dancing to a celebrity DJ.
Actor Idris Elba tried his hand at DJing during the evening, the UK's Daily Telegraph reported, and there was no first dance tune for the couple, rather the Whitney Houston track I Wanna Dance With Somebody was played, where everybody took to the dance floor.
But the fun did not stop when Frogmore House – the famous royal home loved by Queen Victoria – closed it doors, as some guests are said to have staged an after party at top London hot spot Chiltern Firehouse.
Following the exploits of Saturday night, fans of the Royals camped out – hoping for a glimpse of newlyweds Prince Harry and wife Meghan on Sunday morning.
Instead, however, the were treated to a sighting of the Queen who was being driven past the entrance of Windsor Farm shop in a Range Rover.
The Queen regularly attends the Royal Chapel of All Saints in Windsor Great Park on Sundays.
The Queen was seen being driven back to Windsor Castle soon after the morning service at the Royal Chapel of All Saints in Windsor Great Park had finished.
As a few Windsor Farm shop regulars watched, her Range Rover swept into a side entrance onto the castle estate.