Billionaire investor Mike Novogratz is betting big on digital currencies like Bitcoin and Ether.

"Ten percent of my net worth is in this space," Novogratz said at a forum held at the Harvard Business School Club of New York Wednesday. He declined to say exactly how wealthy he is, but he's a former hedge fund manager at Fortress Investment Group and a Goldman Sachs partner who made the Forbes billionaire list in 2008.

It's the "best investment of my life," Novogratz said.

Bitcoin was worth under $500 a year ago. Today the digital currency trades at over $1,200. Back in 2013, Novogratz predicted Bitcoin's value would soar. He remembers people laughing at him at the time.

Since then, Bitcoin's price has been on a wild run. It surged to nearly $1,000 in late 2013 and then fell to under $250 in 2015. It started to fly again last year, around the time of the Brexit vote. It surpassed $1,000 in January of this year again and has kept climbing.

Now Novogratz is saying Bitcoin will go to $2,000.

But he also warned the Harvard Business School Club crowd that there will "likely be a bubble" in digital currencies. The best way to handle it, he argues, is the old Wall Street trick of diversification. Put a little money in a lot of different plays in digital currency.

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For example, Novogratz was also an early investor in Ether. It's another digital currency that has quickly emerged as the No. 2 rival to Bitcoin. Novogratz says he bought Ether when it was trading for about $1. Today it's worth over $48.

Novogratz met Vitalik Buterin, the young Russian brainchild behind Ether at a dinner party at a prominent CEO's home. He recalls that Buterin, then 21, showed up late, which struck him as shocking -- and a bit ballsy. He figured it was worth paying attention to Buterin.

Ether is a currency with a "smart contract" function that gives users additional security and abilities to transfer information in addition to monetary value.

We're witnessing the "3rd inning" of this digital asset revolution, Novogratz predicts. He's not exactly sure how it will play out, but he plans to continue investing in digital currencies and Blockchain, the revolutionary technology behind the scenes that makes Bitcoin work.

Blockchain is literally a digital ledger to record and track transactions. What makes it so technologically advanced is that multiple companies or parties can access the Blockchain and see the history of what happened to an asset.

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Novogratz has emerged as one of the biggest Wall Street cheerleaders of Blockchain, but his bets haven't always gone so well. He exited Fortress in 2015 after the company shut down his Marco Fund for poor performance. It lost around 20% in its final year after his investments in emerging markets, especially Brazil, tanked.

"We have had an extremely challenging two years, and I do not believe the current environment is conducive to achieving our best results," Novogratz said at the time.