Kylie Minogue's former partner spent New Year in Paris with Rosie Huntington-Whiteley, 22, reports The Mail On Sunday.
The couple met when Huntington-Whiteley was modelling at a Victoria's Secret fashion show in New York in November.
A source said: "Rosie made her way out to Paris on Tuesday to spend New Year's Eve with Olivier, where he took her to a family friend's party.
"They have seen each other a couple of times since the Victoria's Secret show but this trip proves they are well and truly a couple."
Martinez, 44, dated Minogue for four years before the couple announced their split in 2007. The French star was praised by Minogue and her family for his support throughout her breast cancer battle.