The video sketch showed Paddington attending a tea party with Queen Elizabeth.
Queen Elizabeth II shared her love for marmalade sandwiches with Paddington Bear, a popular fictional character, as huge celebrations marked the monarch's 70 years on throne.
The fun side of the Queen came to the fore yet again in a surprise on-screen appearance that reminding many of the 2012 Olympics video in which she had joined Daniel Craig as James Bond.
The pre-recorded video sketch showed a nervous Paddington attending a tea party with the Queen, sitting right across to her and pouring tea.
"Perhaps, you would like a marmalade sandwich. I always keep one for emergencies," he said while pulling one out of his red hat.
The Queen's response surprised the beloved children's book and film character, voiced by British actor Ben Whishaw.
"So do I. I keep mine here...for later," the Queen replied with a smile as she too took a sandwich out of her purse.
In awe, Paddington looked at the Queen, wished her a happy jubilee and thanked her "for everything."
A scene outside showed a big gathering and bands playing in honour of the Queen.
In a tweet after his appearance in the video, the character of Paddington tweeted: "If we're kind and polite, the world will be right. Thank you."
The Queen had previously made a camera appearance during opening of the London 2012 Olympics alongside James Bond actor Daniel Craig. The actor, playing his character of the secret service agent, escorted the Queen in a helicopter and parachuted into London's Olympic stadium, with the act being carried out by stunt doubles.
Britain had organized a four-day extravaganza that concluded Sunday, complete with a star-studded concert and a balcony appearance, to mark the monarch's Platinum jubilee.