The two were spotted holding hands as they were leaving the Sunset Marquis Hotel in L.A.
According to E! Online the two were also spotted in West Hollywood, looking “cozy”.
Simpson was wearing a floral romper while her 24-year-old alleged boyfriend opted for a darker look.
Ashlee, whose older sister Jessica gave birth to her second child on Sunday, is a mother herself to 4-year-old Bronx Mowgli Wentz from her marriage to Pete Wentz.