Jen's delighted she's betrothed to Justin Theroux with a stylish Art Deco-style sparkler

Jennifer Aniston was thrilled about actor boyfriend Justin Theroux‘s proposal and she’s happy to show off her impressive engagement ring.

‘It’s a huge emerald-cut diamond,’ a friend of Jen‘s reveals. ‘It’s a rectangle with tapered diamond baguettes on the sides.

‘It’s beautiful.’

Square or oblong diamonds were extremely popular in the Art Deco period. An emerald-cut diamond has rectangular facets parallel to a rectangular top to accentuate its lustre.

Jen, 43, is a lucky girl. She has no doubts about marrying for the second time and can’t wait for the wedding.

‘Just after Jen got engaged, she called all her friends and told them about it,’ the pal tells Life & Style.

‘She was so happy and said she loves the ring. I think she was overwhelmed and overjoyed by the size and beauty of it!’

Before meeting Jen on the set of Wanderlust in May 2011, Justin, 41, dated Heidi Bivens for 14 years.

Jen‘s divorce from Brad Pitt was finalised in October 2005.

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An emerald-cut diamond is a very stylish choice.

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Anna Francis