LG seems to be on course to expand its G series of smartphones, and the grapevine suggests that it has a new phablet - LG G4 Note - in the works, which could give Apple and Samsung a good run for their money.

Rumors are rife that the LG G4 Note will be a top-end phablet, which will throw the gauntlet at the iPhone 6 Plus and Samsung Galaxy Note 4. What's more, the G4 Note will boast a 3K display.

The latest news is courtesy of The Korea Herald, which cites anonymous sources and reveals that the flagship LG G4 would have company in the LG G4 Note.

"Korean tech giant LG Electronics plans to give tough competition in the high-end large screen smartphone market dominated by Samsung and Apple, with its ace in the hole - G4 Note, according to sources," reported the publication. "The sources said Thursday that G4 may not be the only flagship handset of LG Electronics this year as it has a new phablet, called the G4 Note, in the works."

According to the publication, in February this year, the South Korean company registered a trademark for the impending LG G4 Note. A strong possibility exists that the LG G4 Note could well be the mysterious premium handset that would "stand above the G series," which LG's CEO Juno Cho hinted was in the works at the recently concluded MWC 2015.

At the time, Cho revealed that the LG G4 would release in the second quarter of 2015, whereas the premium device would hit the shelves in the second half of 2015.

The LG G4 Note is rumored to sport a 5.5-inch 3K screen, which basically means around a 2880 x 1620 pixel resolution with a ppi of 600. The phablet is also anticipated to be curved like the company's G Flex line. The phablet is also expected to feature a 16MP front-facing camera for selfies and a 5MP rear-facing camera.

Interestingly, a mysterious LG phablet said to be headed for U.S. carrier Sprint has popped up on the FCC. The listing reveals that the device codenamed "LG LS770" will have a 5.8-inch screen and measure 6.07 inches x 2.87 inches. It is also said to come with a stylus in tow and will house a removable 3,000 mAh battery.

Whether the LG LS770 and the LG G4 Note are the same device is unclear at this juncture since the rumored specifications don't match up to the FCC listing.