Paris Hilton says her boyfriend Carter Reum is her reason ''for being so happy''.

The 39-year-old star has celebrated her anniversary with her man and marked the occasion with a sweet social media post gushing over their romance.

She wrote: ''When we first met, I had no idea of the amazing journey I was about to embark on.

''My life was always empty, like I was missing something. But when I met you, I knew you were the one. You've filled my heart with so much love.

''I believe that everything happens for a reason because everything in my life, all the good and the bad, has led me right to you.

''You are my reason for me being so happy and feeling like the luckiest girl in the world! I love making you happy and promise to make you smile forever. Love so much handsome! Happy anniversary! (sic)''

It's not clear what milestone Paris was marking with the loved up Instagram post, as she has taken to the site a number of times this year to celebrate other anniversaries with her man.

Last month, she wrote: ''Happy Anniversary my love! From the moment you walked into my life you changed it in every way. Every day with you has been a blessing. You have shown me what true love really is.

''Thank you for all the incredible memories, the late night laughs and the early morning kisses. Thank you for making me feel safe, holding my hand through this life and proving that good men still exist.''

Her latest post comes after reports Paris is eager to make long-term plans with her beau, and it's said she is already taking steps towards starting a family with the businessman.

A source recently said: ''Paris is not pregnant yet, but is definitely trying.

''She has matured a lot and really wants to settle down and start a family.''

Paris is convinced she's finally found the love of her life in Carter, admitting she was ''just acting'' in some of her previous relationships.

The TV star - who has been engaged three times before - explained: ''I've said 'He's the one' before just because I always wanted to portray 'I'm so happy with the perfect life, the perfect boyfriend', but I never truly felt that.

''I was just acting.''