'The best I’ve felt in my life': Beyoncé reflects on 40th birthday in emotional letter to fans

The pop icon, who turned 40 on Sept. 4, reflected on her milestone birthday in an emotional letter to fans on Thursday. In the open letter, she writes she's finally enjoying the fruits of her labor and making lemonade out of life's lemons. The notoriously private star opened up about how she's "cried tears of joy" because this is "the best I’ve felt in my life."

"The more mature I become, the more I understand and the deeper my joy grows," she wrote in the letter, posted to her official website. "There’s a freedom and liberation knowing that I’ve made it to the other side of my sacrifice. I’m finally giving myself permission to enjoy the seeds I’ve worked so hard to plant my whole life."

Turning 40 has become an age women have culturally been taught to dread because it supposedly signals the end of youth, something women are expected to retain at all costs. But Beyoncé sees it differently: "I'm so grateful to be GROWN, GROWN!"

"Whoever tried to condition women to feel that we are supposed to be old or unhappy when we turn 40 got it ALL THE WAY F’D UP," she wrote. "This has absolutely been the best I’ve felt in my life."

She continued: "This is the first year that I really understand what it means to be alive and to live in the moment. It’s the first time that I have an understanding of how fragile life truly is, how hard life can be at times, and therefore how important it is to stop and smell the roses during the good times. I thought I knew that at 21 or 30…but I didn’t."

Beyoncé thanked her devoted fan base and "every inspiring human who took the time to send me all the beautiful messages" for "your VIDEOS, YOUR POSTS, YOUR countdowns, your playlists and your well wishes."

"I’m grateful to everyone involved, especially, the fans, for the time and level of detail it took to organize such beautiful tributes,” she wrote. "Most of y’all met me when I was 15, and we have grown up together. You bring soooo much joy into my life. I hope my art can continue to bring a little joy into yours. I Love You Deep Deep Deep Deep Deep."

Beyoncé celebrated her birthday all month long with husband Jay-Z on a mega-yacht in Italy, which she frequently documented on her Instagram.

In a star-studded video released on her birthday, stars including Oprah Winfrey, Taylor Swift, Kerry Washington, Jennifer Hudson, Laverne Cox, among others, celebrated the singer's milestones thus far. "You’ve given me and so many others permission to be free to embrace all that we are," Cox said. "You’ve given us a blueprint for excellence: that when we think you can’t surpass yourself, you do." Washington added, "You are such a gift to this world. Thank you for being an inspiration to me, to my kids, to brown skin girls all over the world, to non-brown skin girls all over the world."

"As Virgo Season comes to an end, I hope my fellow Virgos had great birthdays," Beyoncé wrote Thursday.