The pair went to shops in the city's upmarket Woollahra area, including a toyshop where Nicole looked at the Sesame Street cuddly figures.
The pair also bought children's books as well as ladies' fashions.
Leeann Edelmuth, owner of the Marshmellow ladies clothes store in Woollahra where the pair shopped, said, 'Nicole was stunning.
'She looked so pretty.
'I was thrilled to have her come into my shop.'
Nicole has brought her children Sunday Rose and Faith Margaret to Australia to see their extended family.
Antonia has five children from two marriages.
All the children were looked after at Nicole's city centre apartment by her parents, Anthony and Janelle, during the shopping trip.