Charlize Theron revealed what appeared to be a large diamond engagement ring at LAX on Wednesday (23.07.14).
And after the actress was spotted with a large diamond ring at LAX on Wednesday (23.07.14), it has been speculated that her 53-year-old boyfriend has already popped the question.
This lends further credence to reports that the pair are planning to tie the knot in the 'Snow White and the Huntsman' star's native South Africa in the coming months.
A source said: ''They want to get married very soon.''
The pair are thought to also be keen to expand their family after they tie the knot.
Charlize - who has two-year-old adopted son Jackson - is reportedly hoping to adopt a child with Sean shortly after they've exchanged vows.
The insider added: ''Charlize always intended to have another child.''
Sean - who already has 23-year-old daughter Dylan and 20-year-old son Hopper with his ex-wife Robin Wright - has also been bonding with Charlize's young son.
The insider added: ''He is a father figure to him.''
Meanwhile, the loved-up pair - who have known each other for 18 years - have watched each other change over the years and are looking forward to a positive future together as a couple.
The source explained: ''Charlize has seen Sean grow up. He's a wiser soul and much more patient. They're looking to the future with a lot of hope.''