According to today's papers, the I'm A Celebrity... Get Me Out Of Here! host popped the question to manager Ali while over in Australia preparing for the new series of the ITV show.
Dec has yet to confirm the happy news himself but a source told The Sun: "He's over the moon. He is completely and utterly in love with Ali and has no doubt that she's the one."
The insider said that Dec flew to Oz with Ali shortly before I'm A Celebrity work began so they could have some time to themselves before his schedule becomes jam-packed.
They've spent time together in the country before and it holds special memories for them.
Dec, 39, and Ali, 36, have worked together for more than a decade. She served as his manager before romance blossomed.
Congrats to Dec!
You can catch him and TV partner Ant McPartlin when I'm A Celebrity... Get Me Out Here! returns to ITV on Sunday, 16 November at 9pm.
Check out all of this year's jungle campmates here!
Reveal is now on Google Plus! Join us here for the latest pictures, fashion and celebrity news!