Update: On Sunday, Clubhouse confirmed it raised a Series B round led by Andreessen Horowitz. Read more details in our brief.

The race to invest in social audio app Clubhouse is on again. Venture capital firms have approached the startup’s founders in recent weeks about leading its potential next round of funding at a roughly $1 billion valuation, according to four people with knowledge of the discussions.

Investors also have tried to buy Clubhouse shares from existing shareholders at an implied valuation of $1 billion, said one of the people. That figure is 10 times higher than the app’s valuation from eight months ago following a hotly contested investment round, before it was even available on Apple’s App Store. A new deal at a billion-dollar value would be unusual for a social media app at this stage of its life and would also reflect the broader increase in valuations for fast growing, privately held tech firms.