Jen Shah has made a new friend while behind bars .... former "Mob Wives" star Renee Graziano, who's providing the 'RHOSLC' star with advice through letters.

Chris Giovanni, who reps both Shah and Graziano, tells TMZ ... RG has sent JS several letters while in prison, with the most recent one being mailed-off last week.

TMZ has obtained a copy of the note, which reads, "Sending you all love and well wishes. There’s a tattoo on my foot that reads ‘the past was only practice’. We learn from our mistakes or someone elses [sic]."

Graziano goes on to say ... "You are by far doing what is right and Allah sees that so f**k whatever one else thinks." For what it's worth, Shah converted from Mormonism to Islam.

Giovanni tells us Shah loves the letters from Graziano and deeply appreciates her support. As for why Graziano feels so connected to Shah, we're told she's a big believer in those incarcerated deserving a second chance.

As you know, Shah has been locked up at FPC Bryan in Texas after pleading guilty to charges of conspiring to commit wire fraud. However, things are looking up for Shah, who started serving her six and a half years prison sentence in Feb 2023. Her release date has been moved up to November 2027.

Graziano firmly believes a big year is in store for Shah, telling TMZ ... "I know 2025 is a brighter and bigger new year for Jen and anyone who can't find forgiveness isn't as they say a child of God."