Washington, Apr 16 : Just a day after filing for divorce, Hollywood actor Mel Gibson was spotted enjoying a day out with a mystery woman in Costa Rica.

The 53-year-old actor was seen walking barefoot on the beach with a half-unbuttoned shirt while he joked around with his blonde female pal.

At one point, he sticked his tongue out at the woman as she laughed.

"Mel was laughing and joking. He did not look at all worried or concerned," Usmagazine quoted an onlooker as telling Extra.

"You would never have guessed he is going through what could be a very expensive divorce," the onlooker added.

On Tuesday, a 24-year-old Russian pop singer named Oksana Pochepa admitted she had a romantic relationship with Gibson. (ANI)