Rita Wilson's Massive Back Tattoo Has Fans Doing a Double Take

Rita Wilson is turning heads with a side of herself fans don't usually see ... showing off a giant tattoo covering much of her back.

The actress and singer posted a photo Saturday revealing a massive cross tattoo stretching down her back, along with additional ink on her arm.

Rita shared the pic while looking back on a trip ... and the body art quickly became the thing everyone noticed.

Singer Jewel wrote, "Well go sis!" ... while Brandi Carlile added, "What an absolute boss," and Jessica Simpson simply said, "Beautiful."

The huge cross takes up most of her entire back, with an intricate design woven through it ... plus, she's also got a sun-like design on her upper arm, along with lettering underneath.

Rita leaned into the reveal in the caption ... writing, "STRANGER WITH AGE? Who? Me? I'm lovin' it!" while promoting her song "Stranger With Age."

The ink is definitely a departure from the polished red-carpet look fans are used to seeing from Tom Hanks' wife ... but she's clearly been keeping a whole lot of artwork under wraps.

Rita's not the only one in the family who is inked up.

Her son Chet Hanks is heavily inked himself, with plenty of body art covering his arms and torso -- not to mention a big cross like mom's on his back.