The professional dancer declared his intentions with The Saturdays singer, saying he’d treasure their time together for the rest of his life.
“Thank you Mollie,” he wrote to his 49k Twitter followers.
“You have be outstanding throughout this journey, every performance has become a cherished memory that will stay with me for the rest of my life.
“Thank you from the bottom of my heart. You are a STAR @mollieking @bbcstrictly #Waltz #2017 #Semi-Finals.”
AJ, 23, recently admitted he’ll be devastated that he’ll no longer be training with the Mollie every day, after they just missed out on a place in the final.
Speaking to the Daily Mirror newspaper, he said: “We will be friends for life, 100 per cent.
Mollie King records Aj Pritchard change his t-shirt after claiming the pair aren’t an item on This Morning [Instagram]
“She has been an amazing partner. We have so much fun in the training room, we don’t ever want that to end.”I’ll definitely be heartbroken at the end of this because it’s such a fantastic year and it’s all going so well. I wouldn’t change a thing.
“We feel the same way and you’ll see that this week because she gives me a very heartfelt gift. It is something I will cherish.”
The couple’s chemistry has been a hot topic for Strictly Come Dancing fans, with many thinking they are secretly dating.
Bookmakers Coral have even placed odds at 1-4 that they’ll announce they are dating, and 6-1 that they’ll get engaged in 2018.
Spokesman Harry Aitkenhead said: “You can almost see the sparks flying between the pair with their dancing.
“We think it is only a matter of time before she confirms that they are now a couple.”