They both play as centre-backs for PSG and represent the national team together. David Luiz and Thiago Silva also both have miniature versions of themselves.
The cute lookalikes were first spotted in the crowd during last summer's World Cup and ahead of the upcoming Copa America, have made a reappearance.
Lyan and Murilo had a chance to get closer to their larger selves when they were mascots for Brazil's game against Mexico. It allowed them to walk out with Luiz (Silva was on the bench) and join him for the singing of the national anthems.
Luiz and Silva then spent some time with the kids after the match, with the Brazil stars posting pictures and video of themselves with the mini-lookalikes on Instagram.
Brazil would go on to win the game, beating Mexico 2-0. Liverpool's Phillipe Coutinho opened the scoring.