Tom Hanks and Rita Wilson have quietly welcomed a new granddaughter eight months ago, In Touch is reporting exclusively.

“Tom and Rita are really excited to have a new granddaughter,” a source says. The couple’s troubled son Chet, 26, conceived his daughter during a drug-fueled one-night stand with a woman named Tiffany.

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“Tom’s had a lot of issues with Chet over the years, given Chet’s drug and alcohol issues, but this baby has changed all of that,” says the source.

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“Chet’s now sober and is currently working as a drug counselor. He lives in Santa Monica and pays $2,800 a month in rent, with the help of his dad. He’s telling everyone that this baby truly changed his life.”

“Chet is financially supporting the baby, of course, with Tom’s help,” the source says, adding that Tom and Rita don’t mind.

“They adore that baby and even spent Halloween with her. She will always be loved and taken care of by the Hanks family.”

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