She waves to her peers before putting a hand over her mouth as her face appears to express shock at the selection.
Footage also includes clips of a young Meghan parading around a convertible with a tiara and a prom dress.
It comes Meghan’s family will unveil a series of new family tapes of the Duchess of Sussex in an upcoming bombshell interview.
Meghan’s half-siblings, Samantha Markle and Thomas Markle Jr, will be joining forces with dad Thomas Markle on Sunday to send an “extraordinary message” to their estranged half-sister in their last video appearance ahead of King Charles’s Coronation.
Announcing the upcoming broadcast, Channel 7’s Taylor Auerbach wrote on Twitter: “WORLD EXCLUSIVE: This Sunday on @7NewsSpotlight – Meghan Markle as you’ve never seen her before.”
“For the first time, the Markles unite with an extraordinary message on the eve of King Charles III’s coronation. These hidden tapes will stun the world! Only on @Channel7.”
In a promotional video of the interview, a VoiceOver can be heard saying: “The world has never seen Meghan like this, the homecoming queen.”
The three Markles could be seen reviewing the footage together on a sofa, Samantha laughing alongside her father and brother.