The former Broadway dancer also admitted that he is a YouTube personality whose page has racked up nearly 10 million views.
Fearing his celebrity status would hurt his chances for the $500,000 grand prize, Grande had been keeping the information to himself. But his shrewd gameplay has already made him a target for eviction. Just last week, head of household Nicole Franzel talked about ousting the 31-year-old from Florida.
Before heading into the Big Brother house, Grande – whom viewers eventually voted to become a member of the secret Team America – discussed his "complicated" strategy with PEOPLE.
"I don't want people knowing that I have a social media following and that Ariana Grande is my sister because I feel like both of those things will put an unnecessary target on my back," he said. "They will assume that if there is an America's vote or America's player that I will win it because I have a viral following. So if I am recognized as soon as I get into the house, I have to win and I have to do damage control."
Though Grande successfully kept his secret, he came clean after learning this week's evicted houseguests would end up on the jury, the panel that eventually crowns the winner.
The move goes along with his plan before entering the game.
"I think the jury needs to know," he told PEOPLE. "I don't think it is something that will win me points with the jury if I blindside them with it at voting night, so I would probably want to slip it in before the jury starts getting evicted."
Meanwhile, it's no secret who his biggest fan is outside of the house. On Thursday, Ariana attended the live show to cheer on her big brother, posting an Instagram photo with host Julie Chen.
It's unclear whether Grande's confession will play out on Sunday's episode of Big Brother, a source tells PEOPLE.
Big Brother airs Sundays and Wednesdays at 8 p.m., and Thursdays at 9 p.m.