The popstar has been relatively quiet on social media about her brother's stint in CBB but now he's facing eviction, she's taken to Snapchat to plead for votes.
While playing with a filter, she said: "UK babes, I need you to help my brother. He's on Celebrity Big Brother UK and he's up for eviction so I need you to help because he's my brother and I love him so help!
"Thank you! I love you and appreciate it. You're all family, so come though."
While she's been pretty silent about Frankie on social media, Ariana did send a video message to her brother in the CBB house last week, as part of the shopping task that required housemates to complete challenges while not getting distracted by their loved ones.
Her message read: "Hi Frankie, it's me, your sister. I just wanted to say how much I love you and how proud I am of you. I've been watching and you're killing it. I'm so proud of you for being a fan favourite every single week.
"I'm so proud of you for being yourself. I miss you and can't wait to see you. I have so much to tell you, so much music to play you. So much has happened and I can't wait for you to come out. Come home soon – but not too soon! Win first! I love you, I miss you and I can't wait to see you."
Frankie faces tonight's double eviction alongside Bear, Sam Fox, Ricky Norwood, Marnie Simpson and Katie Waissel.