August 20, 2012 - 14:40 BST hellomagazine.com Justin Theroux proposed to Jennifer Aniston on his birthday Justin Theroux looked like the cat who got the cream as he strolled through New York's East Village on Monday. The actor is clearly on top of the world after popping the question to his girlfriend of one year, Jennifer Aniston. CLICK ON PHOTO FOR THE COUPLE'S LOVE STORY The normally brooding star, wearing a grey t-shirt and jeans, grinned at photographers and flashed a peace sign as he made his way to his motorbike. Justin proposed to Jennifer on his 41st birthday, presenting her with an emerald cut diamond to seal the deal. The Friends beauty was said to be "overwhelmed" by the sparkler. A source tells Life & Style magazine: 'It's a rectangle with tapered diamond baguettes on the sides. It's beautiful. "Just after Jen got engaged, she called all her friends and told them about it. She was so happy and said she loves the ring. "I think she was overwhelmed and overjoyed by the size and beauty of it!"