The Queen shook hands with Bob the Builder in a visit to the firm which creates the hit children's BBC show.
Bob took time out from building to meet the Queen
She joined Prince Philip at HIT
Entertainment in London to honour it as one of the winners in the Queen's Awards for Enterprise.
The Queen said "good morning" as she took the construction worker's hand.
Nine senior royals are marking British Enterprise day by visiting businesses and factories across the country to celebrate British enterprise.
In the evening a reception is being held at Buckingham Palace for winners.
The Prince of Wales, the Earl and Countess of Wessex and the Princess Royal are among those carrying out visits throughout the UK.
The Queen and Prince Philip toured children's TV producers HIT Entertainment which owns the rights to hits such as Bob, Thomas the Tank Engine and Pingu the penguin.
They were shown an excerpt from an episode of Bob the Builder - whose co-characters include business partner Wendy and several pieces of construction equipment.
The Queen shared a laugh with Jackie Cockle, who helped develop the original concept for Bob.
"I told her that everybody who worked in animation was quite obsessive with it and divorced from reality. She said that must be really nice," Jackie said
The monarch was also presented with a copy of the book Guinness World Records 2005 - in which she features several times.
She is the longest reigning living Queen, the richest Queen, has her likeness on the most denominations of coins, and spends time in Windsor - the largest
inhabited castle in the world.
The Queen's Award for Enterprise was set up in 1966 and is the highest honour a business can receive from the government.
The awards are presented in three categories - innovation, international trade and sustainable development.