George Clooney has resigned from his role as a "messenger fo peace" for the United Nations.

The actor, who recently got engaged to girlfriend Amal Alamuddin, served with the UN for six years after raising awareness about the crisis in Darfur, Sudan, in 2008; and on Tuesday the UN confirmed the news.

UN spokesman Stephane Dujarric broke the news in a statement, saying, "After six years in this role, Mr Clooney feels it is time to retire his official role as messenger of peace.

"The competing demands on their time from their professional and advocacy lives sometimes make it difficult for high-profile individuals to carry out a formal United Nations role."

Clooney proposed to Alamuddin, an attorney who speializes in international law and shares Clooney's passion for human rights, last week. The actor gave her an emerald-cut diamond ring estimated to be seven carats, and the platinum setting alos contains two tapered baguettes.

"They want the people they love to know that this is real," a source told People magazine, "and that they plan on being together forever."