The massive 'secret' Meghan, Prince Harry kept during first public outing

Prince Harry and Meghan were apparently keeping a massive secret when they made their first public appearance together.

After a year of dating, the couple made their first public debut at the 2017 Toronto Invictus Games, where they were seen holding hands and smiling while making their way to watch wheelchair tennis.

However, according to the biography Finding Freedom: Harry and Meghan and the Making of a Modern Royal Family, the couple were hiding something major — they were already engaged to be married.

The former actress reportedly hinted at the news by wearing a simple white, button-down shirt — a style often referred to as a "husband shirt".

Two months later in November, Clarence House announced Meghan and Harry's engagement, but the pair never revealed the exact date of when he got down on one knee.

Meghan Markle and Prince Harry at the 2017 Toronto Invictus Games. Photo / AP

"It happened a few weeks ago, earlier this month, here at our cottage; just a standard typical night for us," Harry said during their engagement interview.

Meghan chimed in saying that the proposal happened on a "cozy night" when the pair were making roast chicken for dinner.

"It just – just an amazing surprise, it was so sweet and natural and very romantic," she said. "He got on one knee."

Finding Freedom, co-authored by Omid Scobie and Carolyn Durand, chronicles the life of the Duke and Duchess of Sussex, examining everything from the beginning of their romance to their historic "Megxit" announcement.

A spokesperson for Meghan and Harry said the two "were not interviewed and did not contribute to 'Finding Freedom'."