The Hollywood star, who is currently filming his new movie Fury in Hertfordshire, happily queued for rides like any normal guest. He was dressed down in sunglasses, a black jacket and trousers, while his children were wrapped up in jumpers, jeans and boots.
Brad and his children were spotted sitting on a little green boat on the Fairytale Brook ride, which tells the story of Little Red Riding Hood. They were also photographed getting off a pirate ship ride, while Knox and Vivienne also tried a fishing game on a stall.
According to one Twitter user, Chloe Howl, Brad spent a lot of money on one particular game, run by her sister Sophie.
"He spent over £40 playing my sister's game again and again and won a prize EVERYTIME," she tweeted.
His wife, Angelina Jolie is on the other side of the world with the rest of their children. She has been preparing to work as director on Unbroken in Australia.
While Brad caused quite a stir on his surprise visit to Legoland, he recently met a D-Day veteran who had no idea who he was. Peter Comfort, 90, visited Brad on the set of Fury and admitted that he had to use Google beforehand as he "didn't have a clue" about the Hollywood star.