The singers dated as teens in the early 2000s before a love triangle with Lindsay Lohan tore them apart, and Carter clearly hasn't gotten over their young dalliance.
"Don't be that stupid d–– that loses the love of your life forever. Like me…" he Tweeted Wednesday. "I'll spend the rest of my life trying to better myself to get back to her. I don't care what ANY of you think."
When a fan asked Carter, 26, if he was referring to Duff, he answered simply, "sure am."
L. Cohen / Wireimage
For the record, there's no bad blood between Duff and Lohan, who's set on rehabilitating her career.
"We are both adults and whatever happened, happened when we were young," the former Lizzie McGuire actress told PEOPLE in 2007 of the Disney darlings' feud. "It's over."
@closch3 sure am.— aaron carter (@aaroncarter) March 5, 2014