The news comes two years after the actors got engaged following a whirlwind romance after meeting on the set of 2012’s Wanderlust.
A source told a US magazine: "It's really happening! Jen is excited beyond belief. She says it will be the best day of her life."
HOW TO GET ARMS LIKE JENNIFER ANISTON
But pals of the Friends star claim that she is keeping details of the wedding close to her chest.
The insider added: "If you try asking, she'll change the subject to keep everybody guessing.
"Neither of them wants a huge, glitzy wedding."
Jen’s 43-year-old fiancé previously revealed that he was beginning to feel the pressure to make an honest woman out of his famous other half.
He said in an interview: "There is this hum of pressure that - I can't stress enough - I just don't pay any attention to ... We're just doing our own thing. We are completely happy, obviously, but we're not on anyone else's timeframe."
Before dating Jen, Justin was in a long-term relationship with ex-girlfriend Heidi Bivens.
Jennifer was previously married to Brad Pitt, but the pair split in 2004.
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