Jennifer Aniston Plans Justin Theroux a Weekend Birthday Bash

By Jeff Nelson

08/09/2013 at 02:45 PM EDT

Justin Theroux and Jennifer Aniston

John Shearer/Invision/AP

Jennifer Aniston is throwing a birthday party for fiancé Justin Theroux – who will turn 42 Saturday – at their newly renovated Los Angeles home.

Saturday marks another milestone in the couple's relationship: It's also the one-year anniversary of their engagement.

A flurry of reports about the birthday party has launched speculation about a possible surprise wedding for the pair. If that were to happen, though, the couple wouldn't have much time for a honeymoon: Aniston is due in Europe early next week to promote her new comedy, We're the Millers.

While there have been reports the couple has pushed back their nuptial plans, the actress, 44, has been adamant in saying they are simply taking their time.

"We just want to do it when it's perfect and we're not rushed ... We already feel married," Aniston told the Associated Press in July.