It appears Aaron Carter still isn't over his ex.
The 26-year-old singer -- who's been vocal in the past that he still loves his ex-girlfriend Hilary Duff -- posted an Instagram pic of him watching Lizzie McGuire -- arguably Duff's most famous role -- with the caption: "Merry Christmas, Lizzie McGuire.' #IWantCandy #AaronCarter #Flashback I never actually watched this before."
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Carter was watching the episode that he guests stars in and later tweeted: "Apparently a lot of girls were super pissed when I kissed Lizzie McGuire."
This wouldn't be the first time Carter has doted on Duff this year. Upon hearing that Duff had separated from her husband Mike Comrie, Carter tweeted in March: "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."
Duff eventually had to respond. "I keep seeing that, that he keeps doing that," she told BuzzFeed about her ex's tweets. "I don’t know how I feel. I mean, that was so long ago, and obviously I’m still married, and I have a baby and we kind of just … Yeah, don’t know each other … so … yeah."
Back in April, Carter told ET that he "absolutely" still loved Duff. "I don't know who she is today, she doesn't know who I am today, but I would sweep her off her feet if I ever got a chance to again and fix what I did wrong."
VIDEO: Hilary Duff Open to Reprising Her Lizzie McGuire Role!
Duff and Carter dated when they were just 13 years old. Carter was famously caught in a love triangle in 2002 between the Lizzie McGuire star and Lindsay Lohan, whom he started dating after her.
Check out his entire declaration of love to win back Duff in ET's full interview.