Jennifer Aniston and Justin Theroux have reportedly put their wedding on hold again.

The 'We're The Millers' star, who got engaged to the screenwriter on his 41st birthday in August 2012, was busily planning their nuptials in September but recently put everything on ice, including her desire to have a baby, in order to focus on her career.

A source close to the former 'Friends' star, 44, told People magazine: ''She had included her friends and seemed excited [about the process].''

But the insider said that ''Jen said she needed to focus on work'' recently.

Jennifer, who was previously married to Brad Pitt, is no longer enthralled by the idea of having children.

The source added: ''There was a lot of baby talk in the past, but she is not focused on it. She's aware her age makes it more difficult. Her attitude is, 'If it happens, great, but if it doesn't, it wasn't meant to be.' ''

The couple, who fell in love on the set of their movie 'Wanderlust' in 2010, previously postponed their summer wedding to complete renovations on their new home in Bel-Air.

Earlier this year, the actress insisted she already feels married to Justin.

She said: ''We just want to do it when it's perfect, and we're not rushed, and no one is rushing from a job or rushing to a job. And, you know, we already feel married.''

Justin was among a huge number of celebrity guests, including Gwen Stefani, Gavin Rossdale, Gwyneth Paltrow and Reese Witherspoon, at Robert Downey Jr.'s party for his wife Susan's 40th birthday in Sausalito, California, over the weekend, but Jennifer did not attend the event.