North West, 8, sends sassy message to her cousin True Thompson at her birthday bash: 'Four sucks!'

True Thompson Dances With Cousin Stormi At Her Cat-Themed 4th Birthday Bash: Watch

Khloe Kardashian's Daughter True Thompson Celebrates at Purr-fect 4th Birthday Party

Khloe Kardashian's daughter True Thompson celebrates her upcoming fourth birthday during a party