United Kingdom, Sept. 13 -- Britney Spears hopes she can be "the best mommy" to her sons.

The Toxic hitmaker was previously estranged from Preston, who turns 21 on Monday (14.09.26), and 20-year-old Jayden, but they have grown closer in recent years. To mark her younger child's birthday on Saturday (12.09.26), she shared a heartfelt message on her Instagram account.

Alongside an older photo of Jayden, Britney - who has her sons with ex-husband Kevin Federline - wrote: "Happy birthday to my handsome young boy oh dear lord we have this beautiful thing called life in front of us, it's such a beautiful delicate thing.

"I hope I can be the best mommy in the world every day of ur life!!!!"

In July, Jayden spoke out to slam "ridiculous" cons...