Sources confirmed to E! News that the 37-year-old Keeping Up with the Kardashians star and 33-year-old club promoter recently got back together after more than a year apart.
"They are back together and giving their relationship a try again," an insider said. "Scott's mellowed out a lot and hasn't been partying."
Kardashian and Disick sparked reconciliation rumors in November after they were spotted together in Cabo San Lucas, Mexico. Us Weekly subsequently reported the pair are living together again and seeing "what happens" over the holidays.
"Scott has been staying at Kourtney's house with her and the kids for the last few weeks," a source said. "He has really cleaned up his act and been well-behaved. Kourtney is always skeptical about how long it will last, but she has been very encouraged to see how much he has been trying."
"They are planning to do everything together over the holidays with the kids and will see what happens," the insider added. "For now, they are taking little steps in the right direction."
Kardashian and Disick split in July 2015 after nine years of on-again, off-again dating. Kardashian and Disick share three children, 6-year-old Mason, 4-year-old Penelope and 23-month-old son Reign.
"Scott decided to turn things around," a source told People last month. "It was like he finally realized that he needed his family. For the past few months, Scott has been amazing ... He has shown Kourtney that she and the kids are his number one priority."
"Kourtney seems very happy. She's always loved Scott. They are living together now and are very happy," the insider added.
Kardashian and her family came to fame Keeping Up with the Kardashians, which airs Sundays at 9 p.m. ET on E!. The star's half-sister Kendall Jenner walked the runway in the 2016 Victoria's Secret Fashion Show this week.