The 52-year-old was also absent during pre-Oscar bashes here and he even skipped the after-parties March 2.
According to sources, the actor is said to be in London for work, where barrister Amal Alamuddin, with whom he has been seen a lot lately, happens to live, reports dailymail.co.uk.
Clooney-starrer Gravity won seven Oscars, including best director for Alfonso Cuaron, and best original screenplay.
Last week, dailymail.co.uk had reported that Clooney took Alamuddin to the White House to meet President Barack Obama at a private screening for his latest movie, The Monuments Men.
Just hours after the screening on February 18, Clooney and Alamuddin were pictured standing intimately at the Round Robin and Scotch Bar at the Willard Hotel in Washington DC in a group that included Clooney's friend and co-star Matt Damon and his wife Luciana, and fellow actor and co-star Bill Murray.
"They looked very much together, George had his arm around her and she appeared to be a girlfriend," an onlooker said.