Actress Megan Fox lost her engagement ring shortly after she accepted a proposal, US Weekly magazine reports.

Her fiancé, Beverly Hills 90210 cast Brian Austin Green, proposed to the Transformers star on the beach outside the Four Seasons Hualalai hotel in Hawaii and gave her a two-carat diamond ring on June 1.

According to a witness, Fox was jumping up and down before the ring, which the two of them picked together at the Excalibur jewelry store in Beverly Hills, dropped in the sand.

"I saw her jumping up and down. Later, I saw a half dozen staff sifting through the sand," the onlooker told US Weekly.

The hotel staff helped in searching through the sand. However, Fox's publicist has confirmed that despite the couple of hours spent in looking for it, the ring was never found.

The jewelry store told StyleList that the ring, estimated by Diamond Information Center expert Francesca Ferrante to be worth $60,000, is a platinum ring from the 1930s and has an old mine cut with filigree sides and pavé diamonds.

This is the second engagement for the couple. They called off their previous engagement in February 2009.