Terri Irwin shares sweet never-before-seen photo of Steve Irwin in honour of their anniversary

Terri Irwin is paying tribute to her late husband and the day they decided to spend forever together.

Yesterday marked 28 years since Steve Irwin got down on one knee to ask Terri to marry him, and she couldn't resist remembering the moment with a beautiful throwback photo of them as a newly engaged couple.

Taking to Twitter, the 55-year-old conservationist shared a never-before-seen heartfelt snap from the day, which showed the Crocodile Hunter embracing his then-fiance.

"It was 28 years ago today, here at @AustraliaZoo, that Steve asked me to marry him," she captioned the photo.

"Life is constantly changing. Love is forever."

The pair - who shared children Bindi, 21, and Robert, 16, together - first met in 1991 when Terri stopped at a small reptile park in Australia where Steve was working as a zookeeper at the time and tied the knot a year later.

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"Right away we were talking about wildlife, and our passions in life and I kept thinking, 'I wonder if this guy’s married,'" she told PEOPLE in a recent interview.

"He said to me, 'Would you like to meet my girlfriend, Sue?' I tried to be cool about it, but I was devastated. Then he goes, 'Hey Sue, Suey, come here.' And his little dog came running around the corner. 'This is my girlfriend, Sue,' he said. I thought, 'Yes!'"

Steve tragically died in 2006 after being struck by a stingray barb while filming for one of his many TV shows off Port Douglas, he was just 44-years-old.