The 'Modern Family' star has posted a sweet message to the 37-year-old actress and her husband David Barry Gray for throwing her the "most amazing graduation party".
She wrote on Instagram: "Couldn't be more grateful to @shanelle_gray & @davidbarrygray for throwing me the most amazing graduation party ever last night...the amount of love and support they've shown me for the past four years has been life changing. My sister is my absolute best friend and my everything...
"Thank you so much. I couldn't be luckier or more grateful. I was in awe last night and I still am that you guys love me that much to do all of that for me...I never would be where I am today without you two...you guys saved me and taught me to be the person I am today. (sic)"
And the 18-year-old star went on to thank her father and the rest of her family and friends for their support too.
She added: "Dad...I love you!!! Thank you for always being there to support and love me as well and always put a smile on my face no matter what :). I'm so grateful for the bond we now share ...
"Anddddd thank you SO MUCH to all of my amazing family members and friends that flew in to celebrate with us- you guys are the absolute best. Thank you also to the ones who didn't have to fly in...so much love was felt all around last night. Thank you thank you thank you!!!!!! Class of 2016... #uclabound (sic)"
Meanwhile, Ariel - who has been legally emancipated from her mother - previously paid tribute to her sister for being the "most amazing mother I've ever known".
She gushed: "#HappyMothersDay to this insanely beautiful woman inside and out, my sister, my best friend. I love you so much. You are the most amazing mother I've ever known and we are all so grateful for you! (sic)"
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