The calls came after the United States dispatched an aircraft carrier towards the contested region.
According to China's foreign ministry, Chinese President Xi Jinping discussed the North Korean and Syrian situations with US President Donald Trump.
The foreign ministry described the talks between the two nuclear power leaders as a 'new phase' of China-US relations on North Korea.
"I think at this point the common interest between the US and China outweighs North Korea," said Alexander Neal, a senior fellow at the International Institute for Strategic Studies in Singapore.
Speaking to the CNN, Neal voiced his belief that China may be prepared to do some trade-off.
"They (China) want to reign in Kim Jong Un," Neal added.
US President Donald has made repeated calls for China to rein in its unruly neighbor, North Korea.
North Korea has stepped up its missile development and nuclear program since 2016, causing serious concerns in Washington.
The United States dispatched the aircraft carrier USS Carl Vinson after the latest missile test by North Korea last week, provoking a terse warning from Pyongyang.
According to China's foreign ministry spokesman Lu Kang, Trump and Xi agreed to stay in close contact after their first meeting this month.
Kang added that the Wednesday phone call was not an indication of a change of position by China.
The surprise call between the two leaders came after Trump took to Twitter vent his frustrations over the North Korea issue.
"North Korea is looking for trouble. If China decides to help, that would be great" Trump tweeted.