Apple Inc is also widely expected to launch its new iPhone with a bigger screen this year.
The G Pro 2 boasts a 5.9-inch screen, bigger than the 5.5 inch screen of the previous model and one of the biggest on the market. It also has a 1-watt speaker system, a first for smartphones and will be powered by a Qualcomm Snapdragon 800 processor.
The unveiling of the new G Pro had been expected later this month. LG's earlier timing may have been prompted by market leader Samsung's decision to unveil a version of its flagship Galaxy S smartphone on Feb 24 at the Mobile World Congress in Barcelona, three weeks earlier than expected.
The G Pro 2 will be on the market in Korea in late February. LG, the world's fourth-biggest smartphone maker by sales, did not announce a global sales target for the phone.
LG Electronics has improved products and sales sharply in recent years and its global smartphone sales jumped 81 percent in 2013, according to data from Strategy Analytics. Even so, heavy promotion costs for high-end models has seen its phone division post two consecutive quarters of losses.
Credit rating agency Moody's Investors Service downgraded LG Electronics' credit ratings last week, citing persistent pricing pressures and the high costs of marketing new products, particularly mobile phones.