Glen “Big Baby” Davis is clearly not worried about his impending prison sentence … the ex-NBA star was all smiles this week — telling TMZ Sports he thinks it might actually lead him to the body of his dreams.

The former Boston Celtics power forward was ordered in May to spend 40 months behind bars for his role in a scheme that defrauded the NBA’s Players’ Health and Benefit Welfare Plan out of a ton of coin … but when we caught up with him out at LAX, he made it apparent, he’s not sweating things.

The 38-year-old was downright jovial, and said he’s “not nervous” to be thrown in the slammer.

“I feel like I’m going to have good quality time in there,” the former hooper said. “Learn things, meet new people. It’s going to be all right.”

Currently, he’s due to report for his sentence next month — but because he’s appealing the judge’s ruling, there could be a bit of a delay in things.

Nonetheless, Davis is remaining in good spirits … even cracking some jokes about how the time in the pen might save him some funds — and improve his physique.

“Shout out to the ladies out there,” he said. “Write me. I’ll be in there getting fine as hell. When I get out, call me Big Baby Jailbait!”