The 'Poldark' hunk is said to be set to tie the knot with his secret girlfriend, whose identity is not known, in the near future after he popped the question to her recently - less than a year after he split from his partner Nettie Wakefield.
Little is known about his new fiancée but it's believed she's 24 years old - 10 years younger than him - and is a graduate lawyer based in the south-west of England.
A source told the MailOnline: "Aidan is engaged to a 24-year old graduate lawyer from Gloucester."
The news that he's rumoured to be engaged will no doubt come as a surprise to fans as the Dubliner recently admitted that he often questions to meaning of a "soul mate."
He said: "I don't know if I believe in the soulmate thing so much.
"I think you can find somebody you can love your entire life and you can still feel that love decades and decades later. I know couples who've been together 50 years and are happy. But it can be unhealthy to rely on somebody so much."
But his new girlfriend must be special as the 34-year-old hunk has certainly had his fair share of relationships over the years - including a five-year one with Sarah Greene.
He's also dated actresses Charlene McKenna and Lenora Crichlow, and he was adamant that his next girlfriend would not be a screen star or in the limelight.
He said: "I've been in that world before where you're with someone who does the same thing and it can be quite difficult because that's all you are."