Rob Gronkowski's $45,000,000 net worth had surprise boost decade after forgetting about $69,000 Apple investment

When was the last time you remembered something you did years ago?

It's usually embarrassing, like that awkward comment you made on a first date which completely killed the vibe. Or maybe it's something stupid, like accidentally leaving the oven on and almost burning the house down.

Either way, it's unlikely anything you did led you to gain a significant amount of money.

But NFL legend Rob Gronkowski found himself in quite the opposite situation.

Rob Gronkowski is worth $45 million (Mike Ehrmann/Getty Images)

Back in 2014, he invested $69,000 in Apple stock on the advice of the man who'd built his house.

Gronk - as he's better known - admits he had 'no idea' what he was doing, and told Fortune: “I [had] never been involved in stocks. I really didn’t know how stocks work. So I was like, ‘All right, let me do this, man.'"

While that's a significant amount of money for the average person to risk, it's practically loose change to Gronk.

The tight end has earned millions throughout his career - including a six-year $54 million contract with multi Super Bowl winning New England Patriots.

Anyway, Gronk forgot all about the investment until some two and a half years later.

Gronk made the $69,000 Apple investment in 2014 (Sean Gallup/Getty Images)

And to be fair, when your net worth is $45 million, I'm sure it's easily done.

Gronk's money had more than tripled to $250,000 when he finally checked in on it. And today, it's worth more than half a million dollars, providing a nice little boost to his net worth.

Gronk says: “Now to this day, I have over $600,000 in Apple stock, all because of the investment I made in 2014 having no idea what I was doing, but just listening to the guy that built my house here in New England."

And Gronk is certainly grateful for the financial advice.

Despite not knowing about stocks, Gronk's been pretty smart with his millions (Kristina Bumphrey/Variety via Getty Images)

He added: “Let me tell you, he built my house, and he gave all the money back to me by telling me to invest in Apple."

While Gronk may not have known much about stocks and shares, he's always been sensible with his money.

Over the course of his 11 seasons in the NFL, he earned an impressive $70 million in salary. However, according to his 2015 autobiography It’s Good to Be Gronk, he didn't touch one penny of his fortune.

Instead, he lived off endorsement money from brand deals, thought to be worth tens of millions of dollars.

His off-field brand deals have included Dunkin’ Donuts, T-Mobile, and USAA.