The former Lioness, 38, cut an elegant figure in a sleek and sophisticated halter neck dress in a rich chocolate hue. Complete with a backless cut, figure-sculpting fit and a fishtail skirt, Alex's monochrome ensemble boasted runway-worthy perfection.
The One Show host slipped into open-toe sandals and let her brunette tresses tumble past her shoulders in beachy curls. Adding to her beauty glow, Alex donned fluttery false lashes, golden bronzer and caramel-toned lipstick.
The sports commentator joined the Beckhams on the red carpet before hosting an on-stage panel discussion with David before the first episode aired in front of a private audience.
"This series is a love letter to two things. To my football, and my family," announced the former Manchester United striker.
As the synopsis aptly puts it: "From his humble working-class beginnings in east London, his drive and determination to win, and the battle to find a balance between ambition, love and family, David's story is one of immense ups and downs."
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The series promises to take the viewer on a rollercoaster and in doing so, "builds a surprising, personal and definitive story of one of the most recognisable and scrutinised athletes of all time."
Alex has become somewhat of a red carpet maven in recent months, having made her mark on awards season with a fleet of spellbinding outfits at the Grammys, BRIT Awards, BAFTAs and more.
One of her best sartorial moments was arguably at the premiere of The Little Mermaid back in May of this year.
Making a splash in a spellbinding asymmetrical gown, Alex's textured dress consisted of a one-shouldered neckline, a ruched bodice and silhouette-enhancing fit crafted from a glittering ruffled crepe which added to her mermaid-like aesthetic.
Alex perfected the siren-like dress code with a 'wet look' hairstyle, slicking her raven hair into a sleek middle parting and letting it fall past her shoulders in beachy waves.