The couple - who have been dating since earlier this year - have sent festive greetings to their close family and friends and made donations in their names to the St Jude's Children's Research Hospital in Memphis, Tennessee and the Best Friends Animal Society in Utah.
According to gossip website laineygossip.com, the card greeting reads: "We wish you and your family a holiday season full of happiness & joy.
"A donation has been made in your name to St Jude's Children's Research Hospital and Best Friends Animal Society.
"With warmth and love, Jen and Justin (sic)."
Jennifer and Justin are planning to spend the festive season with her father, former 'Days of Our Lives' star John Aniston and his wife Sherry as John is impressed with his daughter's boyfriend and is hoping they will wed soon.
A source said: "Justin and John got along great from the moment they met. John feels that Justin has been wonderful for his daughter and says he's never been Jen happier.
"John would love nothing more than to see them walk down the aisle. He's told Justin he's willing to do whatever he can to help."
Now that Justin and John have hit it off so well, they are really looking forward to spending the holidays together. And of course John is thrilled that he'll have Jen around more."