Katharine McPhee dazzles in silver as she and beau David Foster celebrate Elton John's AIDS Foundation
Katharine McPhee knows how to make an entrance.
The Broadway star was a show-stopper in an elegant silver gown as she arrived to The Argento Ball in Windsor, England for the Elton John AIDS Foundation on Wednesday.
Katharine, 34, and beau David Foster, 68, were among the countless number of celebs and dignitaries on hand to celebrate the silver anniversary of Sir Elton's impactful AIDS foundation.
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![Tying the knot: The music producer - who has already been married four times - proposed to the Smash actress on Sunday](https://i.dailymail.co.uk/i/newpix/2018/06/27/23/4DB4382800000578-0-image-m-35_1530139902624.jpg)
High Society: Katharine McPhee, 34 and beau David Foster, 68, attended The Argento Ball in Windsor, England for the Elton John AIDS Foundation on Wednesday
Katharine documented a snippet of her grand entrance in a video she shared on Instagram.
Part of it shows her strutting down a black carpet in her full length gown that can best be described as both elegant and sexy.
The backless design came up to the neckline in the front as it hugged her petite figure. It also had a slit going up the left side, which allowed for her to show a little leg at her discretion.
She paired the dress with some pointy black ankle boots and a matching black hand-purse.
Her trademark brunette tresses were left long and loose as they cascaded to her shoulders.
As for David, he looked elegant in a classic black suit, black tie and black dress shoes with a white button down dress shirt.
![Strike a pose: Katharine stunned in a silver full-length gown; David and Katharine chatted it up with Victoria Beckham and Christina Estrada at the gala](https://i.dailymail.co.uk/i/newpix/2018/06/27/23/4DB4647400000578-0-image-m-36_1530139920617.jpg)
Strike a pose: Katharine stunned in a silver full-length gown; David and Katharine chatted it up with Victoria Beckham and Christina Estrada at the gala
Katharine also shared a photo on her Instagram of her with singer-turned-designer Victoria Beckham with the caption, 'SPICE UP YOUR LIFE.' The former Spice Girl looked amazing in a sleek black gown that showcased her slender but curvy figure.
The Elton John AIDS Foundation has been going strong for 25-years. It's mission since its inception has been to create an AIDS free future in order to make the biggest possible difference to those living with HIV.
The foundation's achievements include: reaching millions of people across 26 countries with the HIV information, support and care to save their lives and protect those they love; preventing almost a million babies being born with the HIV virus; and helping to leverage more than £300 million in additional funding from governments and funding partners.
Global HIV treatment has expanded from less than 300,000 people to over 20 million since the foundation's first ever summer ball back in 1999.
![Musical: The couple both have musical careers; David is a business mogul in the industry and Katharine is currently singing in the Broadway musical Waitress](https://i.dailymail.co.uk/i/newpix/2018/06/27/23/4DB4382C00000578-0-image-m-37_1530139935715.jpg)
Musical: The couple both have musical careers; David is a business mogul in the industry and Katharine is currently singing in the Broadway musical Waitress
Katharine is on a brief hiatus from her role as the lead in the Broadway version of Waitress.
Her limited run on the show was supposed to end June 17, but it went so well she extended her limited engagement through August 19.
She will return to the stage as Jenna July 5.
Katharine began performances at the Brooks Atkinson Theatre April 10.
![Posh ladies: Katharine shared a picture on Instagram of her with with singer-turned-designer Victoria Beckham with the caption, 'SPICE UP YOUR LIFE'](https://i.dailymail.co.uk/i/newpix/2018/06/28/00/4DB4B47600000578-5894323-image-a-39_1530140827351.jpg)
Posh ladies: Katharine shared a picture on Instagram of her with with singer-turned-designer Victoria Beckham with the caption, 'SPICE UP YOUR LIFE'
![Glamorous: Katharine stopped for some pictures with Siran Manoukian at the Argento Ball for the Elton John AIDS Foundation](https://i.dailymail.co.uk/i/newpix/2018/06/28/02/4DB4434600000578-5894323-Glamorous_Katharine_stopped_for_some_pictures_with_Siran_Manouki-a-116_1530148773865.jpg)
Glamorous: Katharine stopped for some pictures with Siran Manoukian at the Argento Ball for the Elton John AIDS Foundation
The American Idol alum and her music mogul beau were friends for over a decade before they began dating in May of 2017.
They consistently avoided commenting on dating rumors, but have never shied away from public displays of affection and attending high profile events together.
She eventually confirmed they were indeed an item during a night out at the 2018 Met Gala in May.
![Happy couple: Katharine and David have reportedly been dating since May of 2017; seen in March in West Hollywood](https://i.dailymail.co.uk/i/newpix/2018/06/28/02/4DA8F61B00000578-5894323-Happy_couple_Katharine_and_David_have_reportedly_been_dating_sin-a-117_1530148773875.jpg)
Happy couple: Katharine and David have reportedly been dating since May of 2017
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