China’s relationship with South Korea has been testy since Seoul allowed the deployment of a U.S. anti-missile system on domestic soil, but that may soon change as the world’s second-largest economy needs a few favors from its neighbor too.

South Korean President Moon Jae-in arrived in Beijing on Wednesday and will meet Chinese President Xi Jinping on Thursday. This comes after China and South Korea in October agreed to work to get their relations back on track after a year-long standoff over the deployment the U.S. Terminal High Altitude Area Defense (THAAD) system.

The deadlock hurt trade and South Korea’s business interests in China but the two countries are now exploring opportunities to work together against the backdrop of an unpredictable North Korea.

“There is no question that China is extremely worried about the downward spiral of the North Korean crisis,” said Christopher Hill, former U.S. ambassador to South Korea and the current dean of the Josef Korbel School of International Studies at the University of Denver.

“There seems to be no hope coming, and I think there’s going to be an effort with the South Koreans to see if there’s anything that can be done,” Hill told CNBC on Thursday.

Beijing is worried about the short-term fallout from the North Korean crisis as President Donald Trump is untested in the region, Hill said.

“The basic concern is that the Trump administration is not willing to move in any new way on North Korea, but neither are the North Koreans,” said Hill.

“There must be a great deal of concern of what could happen in the short run not just because of North Korea, but because of the combustible relationship there is between North Korea and the United States,” added Hill.

China may also have other items on its wishlist.

“The hope is that South Korea can play the kind of role that the U.K. has played in European politics, that is South Korea can somehow deliver — in the Chinese view — a more reasonable U.S. (foreign) policy,” said Hill.

In what is seen as a signal of goodwill, Beijing has started lifting curbs on group tours to South Korea and on K-pop, which is popular in China.