The model announced earlier this month that she and British actor Jamie Belman had cancelled their June wedding and sources close to Petra say she has turned to Sean for support.
The pair - who briefly dated in the early part of 2008 during one of the actor's splits from now ex-wife Robin Wright - were recently seen enjoying a dinner in New York.
A source told the New York Post newspaper: ''Petra was all over him like crazy. She was rubbing his shoulders and rubbing his leg. She was hanging all over him. Sean looked like he was playing it cool. But they did leave the restaurant together.''
Petra and Jamie enjoyed a whirlwind eight-month romance before getting engaged in January 2011 and insist they ''remain close friends'' despite their break-up.
A statement from Petra's agency, Next Models, read: ''Petra Nemcova and Jamie Belman confirm their separation. They remain close friends and thank their families for their continued support during this time. There will be no further comment on the matter.''
The Czech-born model survived the 2004 tsunami in Thailand, which tragically claimed the life of her then-boyfriend, photographer Simon Atlee and has since been romantically linked to singer James Blunt and director Peter Berg.