The pair ended their three-year on-off romance in June (09).
DiCaprio has since been linked with a string of single ladies, including British actress Sienna Miller, while Refaeli was most recently rumoured to be dating Gossip Girl star Chace Crawford.
But sources tell Us Weekly the former couple has grown close again, after the 24-year-old model reached out to her ex - and reportedly enjoyed a secret romantic break in the Bahamas together late last month (Nov09).
An insider says, "She was really upset over the break-up and hasn't stopped calling him.
"They aren't full-on monogamous but are seeing each other again."