Chinese billionaire Liu Yiqian can now fly in first class anywhere in the world for free, after he bought a $170 million painting. Liu Yiqian won a bidding war for "Reclining Nude" painting  at Christie's auction in New York earlier this month. "Reclining Nude" was painted between 1917 and 1918 by an  Italian artist Amedeo Modigliani.

According to New York Times, Liu's wife Wang Wei confirmed that when the sale closed, she and Mr. Liu would be using their American Express card to pay the Modigliani's painting. They would use the points they earn from the payment to have free flights for their whole family: the couple, their four children and two grandchildren.

Ms. Wang said that they are on a one-year payment plan for the painting. She added that it would be a little difficult if they had to pay cash upfront.

Last year Liu used his American Express to pay $36 million for 500 year old tea cup from Ming Dinasty. That purchase earned him 422 million American Express points which can be used for more than 28 million frequent flyer miles for his whole family.

American Express declined to confirm Liu Yiqian's Modigliani purchase and how many points or miles he would earn. But according to Mashable, the $170 million purchase can be done using the card. American Express spokeswoman Elizabeth Crosta said that it is possible to put the purchase on an American Express card. Liu's American Express Centurion Card, which is also known as AmEx black card, has no official credit limit.

By using his AmEx card, Liu will earn 170,400,000 million Membership Rewards points for his painting purchase. According to Daily Mail, Liu's purchase could see him earn up to 2 billion points on his card or 132 million frequent flyer miles. With these points,  Liu would be able to take the first class on 180,000 miles trip from London to New York for 733 times.

Liu could also use his AmEx points for shopping on American Express' online mall. He could buy a 26 carat diamond bracelet for 33 million points or a 29 light crystal chandelier for 10 million points.

Liu Yiqian plans to display his "Reclining Nude" at his Long Museum Pudong in 2017 to mark its fifth anniversary. Liu and his wife opened this private museum in 2012 as they started to collect arts since early 1990s. Liu opened the second branch of his museum, the Long Museum West Bund, in 2014 as a part of government sponsored project.

Almost all of $9.5 million operation costs for both museums this year are undertaken by the couple.