Martina McBride celebrates daughter Ava's 18th birthday: 'You are a true original'

This one's for Martina McBride's baby girl.

The "Independence Day" singer, 56, took to Instagram on Tuesday to celebrate her daughter Ava's 18th birthday.

"My youngest baby. Happy 18th Birthday Ava," McBride wrote in the caption. I am so very proud of you."

She continued, "You are a true original. Maybe the funniest person I know. So smart. Kind. Fun. And complicated in the most beautiful way. We are all learning from you. I love you."

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To mark Ava's milestone birthday, McBride shared a slideshow of photos of her baby girl growing up.

The "Concrete Angel" singer shares three children -- daughters Delaney, 28, Emma, 25, and Ava -- with her husband John, whom she married in 1988.

McBride marked her 35th wedding anniversary last month, sharing selfies of her and John.

"We made it to 35 years! Thirty. Five. Years. Wow. This guy makes me laugh every day and he's a great dad to our 3 girls," she wrote in the Instagram post. "He is a friend to many. But he's my best friend. Love you John."