'Teen Mom: Young & Pregnant': Kayla Sessler Has Surprise Visitor at Izaiah's Birthday in Exclusive Sneak Peek

Teen Mom: Young & Pregnant's Kayla Sessler isn't happy to see an unexpected guest at son Izaiah's 3rd birthday party. In a PopCulture exclusive sneak peek of Tuesday's season premiere, the 22-year-old is looking forward to spending her oldest's big day with boyfriend Luke Davis, their 2-year-old daughter Ariah and close family and friends, despite not hearing anything from Izaiah's father Stephan Alexander. 

"Stephan hasn't reached out to us, but I don't care, because we're celebrating with my friends and family," Kayla says in the preview. Spending quality time together as the kids are introduced by a reptile handler to a variety of snakes and lizards, the party is interrupted by an unexpected knock at the door. When Luke goes to answer, he sees one of Stephan's friends holding a birthday present he says is for Izaiah from the toddler's dad. 

While Luke and Kayla's mom Jaime thank the friend for stopping by, the mood noticeably shifts after he makes his exit. Giving Izaiah the gift without mentioning who it is from, Kayla rips open the card to see what Jaime notes is an especially long message from Stephan. "Izaiah can't read, and I don't really want to read it," she says, putting it aside. Kayla stays quiet while processing the new development, but mom Jamie is fed up. "I wasn't expecting that one," she says. "You can't disappear out of his life and then send him a note. Kiss my a-." 

Prior to Tuesday's premiere, Kayla opened up to PopCulture about where Stephan and his son stand today, confirming that her ex still hadn't seen his son since Izaiah was only a year old. "We leave Stephan behind where he belongs, which is in the past," the MTV star said, adding she was "100%" happy to leave him there. Don't miss Kayla and Luke's story on the brand new season of Teen Mom: Young & Pregnant, returning Tuesday, Sept. 7 at 9 p.m. ET on MTV.