Jennifer Aniston focusing on work following split from Justin Theroux

Justin Theroux and Jennifer Aniston announced last Thursday that they have separated. Photo / AP

Jennifer Aniston's shock split from Justin Theroux sparked meme mayhem as fans imagined her back in Brad Pitt's arms.

Aniston and Pitt's marriage broke up in 2005 and he went on to a relationship with his Mr and Mrs Smith co-star Angelina Jolie.

But rather than seeking solace in her significant ex, the former Friends star is expected to focus on work, as the Daily Mail reports.

Aniston will next star in a drama alongside Reese Witherspoon. Apple signed the pair to a two-season, straight-to-series 20-episode order.

Fans are excited that Jennifer Aniston and her ex-husband Brad Pitt, pictured in 2004, are both single. Photo / Getty

Aniston and Witherspoon are thought to have secured upward of US$1.25 million ($1.69m) per episode for The Untitled Morning Show Project; their huge salaries including fees for executive producing, according to the Hollywood Reporter.

On Monday, as Aniston celebrated her birthday in LA without her soon-to-be-ex husband of two years, Witherspoon shared a picture of the two of them back in 2000, when she guest-starred on two episodes of Friends as Rachel Green's youngest sister, Jill.

View this post on Instagram

Happy Birthday to my work sister #JenniferAniston !! 💕🎂 Wishing you a day filled with lots of love and laughter ! 🎊 #HBD

A post shared by Reese Witherspoon (@reesewitherspoon) on Feb 11, 2018 at 1:38pm PST

But while Aniston's new project sees her focusing on the New York media world, her preference for Los Angeles life is said to have proved a big part of her marriage breakdown.

Despite being born and raised in New York, she much prefers west coast life. Theroux, however, has a wide and varied friendship circle on the east coast.

Theroux, 46, and Aniston, 49, announced their split this week, following increased speculation about the state of their marriage.

In a joint statement, they said: "In an effort to reduce any further speculation, we have decided to announce our separation.

"This decision was mutual and lovingly made at the end of last year. We are two best friends who have decided to part ways as a couple, but look forward to continuing our cherished friendship."

Aniston and Theroux tied the knot in August 2015 in a secret ceremony at their Bel Air, California home.