Amanda Holden's daughter Lexi, 18, is tall and modelesque in glamorous new photo

Amanda Holden was every inch a proud parent as she celebrated her eldest daughter Lexi's final day of school. 

The Heart Breakfast presenter, 53, marked her 18-year-old daughter's major milestone on Instagram, sharing a stunning photo of the duo dressed in head-to-toe glam as they geared up to celebrate Lexi's achievement. 

"Last ever day at school," Amanda began. "A levels done. Could not be prouder of our little @lexi.hughes__ brilliant, funny, resilient and all grown up… the world is yours.

"Go and live the biggest possible life… Mummy Daddy and Hollie love you," the Britain's Got Talent judge penned on Instagram. 

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In the sweet mother-daughter photograph, Lexi towered over her mum in a breathtaking gown by Dolce & Gabbanna. 

With a strapless neckline, structured bodice and elegant full length, Amanda's daughter looked radiant in florals as she paired her dress with strappy heels. 

Twinning with her lookalike daughter, Amanda opted for a white floral dress and square-toe court shoes. 

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The honey-blonde pair caused a stir in the comments with Amanda's 2.3 million Instagram followers, with many rushing to complement the pair's similarities. "Stunning, both of you!" wrote one fan, as another penned: "You could be sisters!"

A third fan sweetly shared: "Lexi takes after her mum, what a beautiful photo." 

Amanda faces a tough parenting milestone

Former West End star, Amanda, who also shares daughter Hollie with her husband Chris Hughes, previously spoke to HELLO! at the Born Free charity gala, where she opened up about her eldest Lexi flying the nest. 

"I want [Lexi] to live the biggest life she can live," she told HELLO!, adding: "So I'll have to say goodbye. But children always come back."

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It's not the first time the mother-of-two has expressed her sadness at her children moving on. Speaking to close friend Alan Carr during an episode of Amanda & Alan's Italian Job, she added: "They say you have 18 summers and then you're lucky to see them. It's so terrible because you wish so much of it away when you're a busy parent. And then you turn around and they're not even there."

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Lexi is said to be exploring the option of living in America post A-levels, and has already been signed by Storm models.