Lily and Hugo were best friends before and during their time at Hogwarts. They were both sorted into Gryffindor together and would spend tons of time with each other, even though they each had friends of their own gender. In their sixth year, Lily started dating a boy from Hufflepuff named Andrew. Hugo was mad that he was losing his best friend, and he was very protective of Lily at that time. He confronted Andrew and told him that if he ever hurt Lily, Hugo would be there to stop it. The two became close friends after that, because when they graduated Hogwarts, they worked at the Ministry together. Many years later, when Hugo was the best man at Lily and Andrew's wedding, he told the story of how he had become friends with the groom after threatening him. Hermione and Ginny were not amused.