The fund raising was first reported by the Wall Street Journal, which also said this round was led by tech fund All-Stars Investment and included Russian tech fund DST Global and Yunfeng Capital, a private-equity firm affiliated with Alibaba Group Holding Ltd Executive Chairman Jack Ma.
All-Stars Investment is led by former Morgan Stanley analyst Richard Ji.
GIC's investment in Xiaomi comes after Singapore state investor Temasek Holdings Pte Ltd [TEM.UL] bought a small stake in the smartphone maker during an earlier funding exercise, a second person said.
The people were not authorized to speak to media on the matter and so declined to be identified. Xiaomi and GIC declined to comment. Ji could not be reached for comment.
Xiaomi brands itself as an Internet company that eschews traditional marketing and sells hardware at low prices as a distribution channel for its real money maker, software and services.
It has been investing heavily in other manufacturers with the aim of building an ecosystem of Internet-connected devices and appliances to extend its reach beyond smartphones.
Nomura analysts said in a report earlier this month that Xiaomi and founder Lei Jun had invested in 43 companies across China's mobile Internet eco-system, including smart device makers, network infrastructure firms, smartphone platform developers, and providers of various mobile internet services.
Xiaomi's investment partners include Shunwei VC, Temasek and Kingsoft, the Nomura analysts said.
(This story was refiled to remove superfluous 'a' from first paragraph)
(Reporting by Saeed Azhar and Gerry Shih; Editing by Christopher Cushing)