Justin Theroux is planning to buy Jennifer Aniston a huge ruby.

The 'Wanderlust' actor wants to give his fiancee the jewel as it represents devotion and the other qualities he wants to show her as a husband.

A source told America's OK! magazine: ''Justin is planning to buy Jennifer a massive ruby because it symbolises devotion, integrity, courage and happiness and he wanted his gift to symbolise what he is offering her as her new husband. Once he finds the right stone, he will have it made into a necklace.''

Justin's choices of jewellery for his fiancee have previously gone down well, with the former 'Friends' star ''overwhelmed'' when he splurged on an eight carat diamond engagement ring.

A source previously said: ''It's a huge emerald-cut diamond. 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!''