"Thank you for taking care of me like your own, love you," Alabama gushed.
Kourtney Kardashian received several sweet messages from her new step children on Mother's Day.
The 44-year-old "Kardashians" star was honored by her husband Travis Barker's kids, Landon, 19, and Alabama, 17, on Sunday.
"Happy Mother's Day @kourtneykardash," Landon wrote alongside a photo of the family at Kourtney and Travis' wedding in Italy last year. "I love you, hope you have a great day."
Alabama also took to her Instagram Story to thank the Poosh founder for seamlessly welcoming her into the family.
She captioned a group mirror selfie that included Kourtney, her daughter Penelope and sister Atiana in Portofino.
"Happy Mother's Day Kourt," Barker gushed. "Thank you for taking care of me like your own, love you @kourtneykardash."
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Shanna Moakler, who shares Landon and Alabama with Travis, also received Mother's Day tributes from her children alongside the reality star. The former pageant queen also shares her 24-year-old daughter Atiana De La Hoya from a previous relationship with whom the Blink 182 drummer maintains a close relationship.
"Happy Mother's Day mom, I love you so much," the "Holiday" singer captioned a group photo of himself smiling arm-in-arm with Moakler and Atiana. "So thankful for you, I hope you have a good day!"
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On the other hand, Alabama shared throwback photos of the 48-year-old model in a series of slides. "Happy Mother's Day momma, I love you lots I hope you have the best day," she wrote. "I'll see you soon."
Atiana also posted a series of old photos to her Instagram Story. One featured her playing piano with Moakler as a baby while others included her late grandmother.
"Happy Mother's Day beautiful mama," she said.