Christina Aguilera marked her 40th birthday on social media with a beautiful note to herself.

In the lengthy post, the chart-topping Beautiful hitmaker reflected on her efforts to embrace the ageing process as she enters a new decade of her life.

“Dear 40, What a beautiful concept… to not only be ‘turning’ 40, but to be ARRIVING at 40!” Christina wrote. “This ever-present social stigma exists around getting older, but I have ALWAYS embraced it! I am forever an old soul and I appreciate the wisdom, grace and beauty that comes with each new year of life.”

Adding that she’s “heard it said that some of your best life is lived in your 40's," Christina continued: "You stop giving a f**k about all the bulls**t… clarity comes over you, and a new intention sets in with every move you make. I truly believe the best is yet to come and I am READY for it.”

Christina also mentioned her two children - 12-year-old Max, who she shares with ex Jordan Bateman, and six-year-old daughter Rain, her child with fiance Matthew Rutler.

“To the rare and beautiful souls who have stood by me for over 20 years and counting, I am eternally grateful for you,” added the Your Body singer. “I am blessed to have the most solid friends around me, a team I believe in that makes me feel supported and heard and of course, my family; my baby boy and girl, the most incredible children one could ever imagine! My heart is full.”