WeWork now boasts a $47 billion valuation.

That's based on SoftBank Group's new injection into the fast-growing American office space provider.

Sources tell Reuters the company led by Msayoshi Son will invest an additional $2 billion in WeWork, bringing its total stake to $10 billion.

The new investment comes from the Japanese internet and telecom giant itself, not its SoftBank Vision Fund, which is also a big financial backer of WeWork.

The SoftBank Group, which owns mobile carrier Sprint, has been publicly bullish about WeWork's prospects.

The company is gobbling up commercial office leases as it provides office space in settings where services are shared for individuals and small firms. But some Silicon Valley investors have been skeptical, dismissing WeWork as an overvalued real estate play that's vulnerable to a downturn in the property market.

The investment comes after SoftBank raised nearly $24 billion last month when it listed its domestic telecom company, SoftBank Corp.

SoftBank Group shares rose nearly 6 percent in Tokyo trading Tuesday.

SoftBank Corp finished almost 2 percent higher.