Mel Gibson Reunites With Daughter Lucia In Australia — But Mom Oksana Grigorieva 'Devastated' By Separation: Inside Their Feud

Too cute! Mel Gibson spent some quality time with his 5-year-old daughter, Lucia, in Sydney this week— but the reunion was bittersweet for Lucia's mom, Gibson's ex Oksana Grigorieva.

In June, a. L.A. judge granted the 60-year-old actor permission to take his little girl to Australia. The father/daughter pair, along with a nanny, enjoyed a sunny Sydney day on July 15.

But Grigorieva, 45, is "devastated" that her daughter will be so far away from her mom's Sherman Oaks, California, home for more than a month, sources exclusively tell RadarOnline.com.

"It's a long time for her to be away from her mother," the insider says of Lucia, here grocery shopping with her dad this week Down Under.

The stunning Russian singer, who split from the star in 2010, is also concerned that Gibson won't have enough time for his daughter.

Gibson, who is in the country directing war drama Hacksaw Ridge, "may not be able to spend much time with her because of his many work responsibilities," the source adds.

The former couple has been at odds over co-parenting their daughter.

"Mel insists on doing the opposite of whatever Oksana proposes," the insider explains.

Dad Gibson "is really focused on Lucy," another source says.

Gibson and Grigorieva currently have joint custody of little Lucia.

An eyewitness says Gibson and his daughter "laughed and cuddled" during their day on the town.