Even though celebrity couple Charlize Theron and Sean Penn are not yet married, reports claim that the pair is as happy as they'll ever be.

Theron, 'A Million Ways to Die in the West' star, confessed to Vogue that she couldn't be any happier with her boyfriend, award-winning actor and director, Sean Penn. The two stars have known each other for eighteen years, and are taking things slow in their relationship. However, Penn was the one who advanced on the friendship and the two upgraded into a full blown relationship.

Reports from kpopstarz.com say that while Charlize brings out the gentle and fun side of the 'I am Sam' actor, 53-year old Penn is said to be "a totally different person around Charlize."

She mentions that it was Penn's irresistible charm and humor that persuaded her feelings for him. Plus, he is said to be getting along well with Jackson, Charlize's two-year-old adopted son. She's also pleased with Penn's relationship to his own son, which gave her a positive take on their relationship. This clearly indicates that the two prominent celebrities have been shedding rays of sunshine into each other's lives.

Theron, having a mindset that it's just going to be her and Jackson for the rest of her life, seems like she suddenly shifted and has been talking about marriage with Penn in the past few weeks. However, the 18-karat yellow gold ring that she was spotted wearing around her finger was just a gift from Penn, and she clarified that they're not yet engaged.

Theron and Penn are set to work on a film together, entitled 'The Last Face'. The film will be directed by none other than Sean Penn and will feature bombshell Charlize Theron. The harmonious relationship between the two seems to be growing stronger each and everyday.