Uber Technologies, Inc. is reportedly closing in on a $1 billion-plus financing deal for its self-driving car unit, a move that could give Uber a critical boost as it gears up to go public this spring.

Tokyo-based SoftBank Group (SFTBY) is part of a pool of investors involved in "late-stage talks" aimed at grabbing a stake in Uber's autonomous car unit, The Wall Street Journal reports, citing sources "familiar with the negotiations."

A spokesperson for Uber declined to comment to TheStreet on the news, and SoftBank did not immediately respond to a request for comment.

The deal comes on the heels of a $7.7 billion investment, inked late last year by SoftBank in Uber's main operations, giving it a 15% stake in the company.

If it goes through, the investment deal would provide a jump start for Uber's efforts to roll out a self-driving vehicle, which have cost hundreds of millions of dollars since 2017 and spurred controversy.

A self-driving Uber car last year struck and killed a woman in Arizona; over the summer, Uber shut down its self-driving truck initiative to focus its efforts on autonomous cars.

Along with SoftBank's Vision Fund, other investors include an unnamed automaker, with the consortium looking to snag a minority share in the unit, according to the WSJ.

The financing deal itself values Uber's autonomous car operation at between $5 billion and $10 billion, the paper noted.

An injection of capital could lighten the load for Uber as it gets ready for an IPO this spring, with the ride-hailing service company valued anywhere from $44 billion to $120 billion, TheStreet has reported, citing varying estimates.