George Clooney ''immediately'' hit it off with his fiancée's family.

The 'Monuments Men' actor - whose engagement to the human rights lawyer Amal Alamuddin was announced this week - visited Dubai to meet the brunette beauty's family in March and bonded with her siblings during a yacht excursion.

A source told PEOPLE magazine: ''They found George very easy to get along with, cool. They felt at ease with him immediately.''

The 52-year-old star proposed to Amal on April 22 and during a private dinner on April 27 she showed off the new ring - an emerald-cut diamond, which is estimated at seven-plus carats.

The couple celebrated the news with close friends Cindy Crawford and her husband, Rande Gerber, in Santa Barbara, where they were also toasting Rande's 52nd birthday.

George and Amal, 36, met at a small charity fundraiser last September and although he was instantly attracted to her it is said she was unimpressed by his Hollywood stature and failed to be won over by his charm.

The hunky actor managed to obtain her number and called her the following morning to ask her out, but had to work hard to get her to agree to meet him.

Sources say when they finally went out she was impressed with his charitable and humanitarian endeavours.