The 45-year-old actress is said to have hosted the party for her best pal and former 'Friends' co-star - who is set to marry Irish Snow Patrol rocker Johnny McDaid - in Beverly Hills, inviting 11 of her closest and friends, including Johnny's mum Pauline. A source revealed: "Jen went all out and had decorated the dining table with green and white bouquets, hand-made mint chocolate truffles and green velvet cupcakes, green and white napkins with shamrock place settings and Celtic charm champagne glasses."
Guests are said to have enjoyed themed treats such as Guinness chocolate cheesecake at the bash at California's Il Pastaio restaurant and Johnny even stopped by to make sure his wife-to-be - who has 10-year-old daughter Coco with ex-husband David Arquette - was having a good time.
The source added to The Sun newspaper: "Johnny even made an appearance at the end of the meal."
The couple - who were introduced by 'Thinking Out Loud' singer Ed Sheeran - sparked rumors they'd already tied the knot earlier this year when Johnny, 38, appeared to be wearing a wedding band on his ring finger during a romantic stroll with 50-year-old Courteney.
Meanwhile, Jennifer - who has been engaged to her 'Wanderlust' co-star Justin Theroux since August 2012 - hinted previously that she thought Courteney should enjoy her engagement and not rush into marrying.
She said: "There is something to enjoying the engagement period I have to say, whether it's three months, one year, two, three, four, five years, who knows, enjoy it. There's no rush."