'It's been amazing to watch him, but it's been frustrating,' she tells Billboard of her brother's time on the show.

If you follow Ariana Grande on Twitter, you know she is fully immersed in the game of Big Brother and fiercely backing up big bro Frankie to win it all.

Watch Frankie Reveal That Ariana Grande Is His Sister on 'Big Brother'

She even speaks the language of the show, urging Frankie to "backdoor" a shady contestant (meaning to put someone up on the block to be sent home at the last minute so they can't save themselves) and celebrating a contestant winning "POV" (Power of Veto, which saves houseguests from going home).

A sampling of her recent fangirl tweets:

.@lizgillies & I r unimaginably excited to hopefully meet the cast of #bb16 1 day. we're straight up bringing autograph books like children. — Ariana Grande (@ArianaGrande) August 17, 2014

frankie don't backdoor zach frankie don't backdoor zach frankie don't backdoor zach frankie don't backdoor zach frankie don't backdoor zach — Ariana Grande (@ArianaGrande) August 17, 2014

When Billboard sat down with Grande on Tuesday -- as she promoted the Aug. 25 release of her sophomore album, My Everything -- she was more than ready to talk about BB, even offering up advice for how her brother can take home the half-million.

"Derrick is running the whole house right now, which is annoying," she said of the undercover police officer, who has kept his job under wraps and is friendly with everyone in the house. "And I feel like if Frankie -- I want to telepathically tell him, 'Just backdoor Derrick!' Because that would be the greatest, bravest move he could possibly make. Oh my God, it would be incredible."

Unfortunately, that telepathic message didn't reach Frankie, who backdoored onetime BFF Zach (RIP #Zankie!) much to his sister's dismay on Wednesday night. Check out her heartbroken tweet:

hating tonight's #bb16 episode. wanna hug @frankiejgrande n then slap some sense into him. grrr. save zach! put up derrick. please. so upset — Ariana Grande (@ArianaGrande) August 21, 2014

But Grande was happy when Frankie finally revealed his big secret last week: You know, that his sister is the biggest pop star in the country.

"I'm just so proud of him, because I love what he did when he came clean and told everybody about his career and what he does and about his family," she said. "I thought that was a very bold move, especially because Derrick -- he's a cop. He's like [mimics Derrick's voice], 'I actually am who I say I am.' Um, but you're not though."

Frankie might've just saved his game tonight!!! werrk @FrankieJGrande! told his whole truth & apologized for playing dirty like a man. proud — Ariana Grande (@ArianaGrande) August 9, 2014

While she really hopes Frankie wins, most of all, she's just ready for him to come home. "It's been amazing to watch him, but it's been frustrating. It's been -- ugh -- annoying. I miss him so much. Like, I miss my best friend. I love him so much. But I'm so proud of him, because this is something he's wanted to do for a very long time."

Since ESP isn't working out for her, Grande is ready to move onto something more drastic, like renting an airplane with a banner behind it to get a message to Frankie as superfans have done in previous seasons. "Don't think I didn't think about it!" she laughed, adding that she's also trying to send him hints through her letters. "I literally thought of every possible code to put in."

Big Brother airs Sundays, Wednesdays and Thursdays -- including tonight's live show -- on CBS.