The Australian rider made the surprise announcement during the BMC media day at a training camp in Denia, Spain. The attempt will take place at the velodrome in Grenchen, Switzerland on February 8.
Dennis moved to BMC Racing in August of this year after leaving Garmin-Sharp in a mid-season transfer. He made his debut for his new team at the Eneco Tour and followed up with a ride at the Vuelta before posting a fifth place finish in the Worlds time trial.
The recent changes to the Hour Record rules by the UCI have sparked successful attempts by Jens Voigt and Matthias Brändle in 2014. The German set a distance of 51.110km in September with Brandle beating it with a distance of 51.852km in late October.
Australia's Jack Bobridge and Britain's Alex Dowsett are both set to attack the record in early 2015, with Bradley Wiggins' attempt expected in June. Dutchman Thomas Dekker has also announced he will attack the Hour Record despite failing to find a place with a major team for 2015.
"I’ve been training towards this since Worlds, ever since I got back on the bike and I really appreciate the team backing the project," Dennis said, before confirming that he would aim for a total distance of 53km in the attempt.
"There’s a number in my head. 52.5km I’d be happy with that but I’m trying to push towards 53km."
Allan Peiper, BMC's Performance Manager added that the American squad were fully behind Dennis' challenge.
"It started out as being just an idea from Rohan and we want to support every rider in our team. We had to take it seriously from the first day and going from an idea of him on a track bike for an hour, this project has morphed into so much more than that. It entails a lot of planning to build to the event in February. It’s exciting and we’re proud to be supporting Rohan."