The tournament was upgraded to a 500 level in 2015 and is held highly among the players on the tour in preparation for Wimbledon.
Dimitrov confirms intention
The Bulgarian tasted silverware at the championships in 2014; a run which aided his quarterfinal upset over Murray at Wimbledon two weeks later.
Dimitrov said: “The grass-court season is going to be a big thing for me with Queen's and then Wimbledon around the corner.”
“I've seen the field, it's going to be very strong again, but I'm excited to see what my form is going to be like.”
He fell in a grueling five-set battle with Nadal but regained his poise to win his native Sofia.
Nestled comfortably at 13 in the ATP singles rankings, Dimitrov is eyeing even more success.
“I feel like I'm a better player, a better person, better everything,” he added.
Stan looking to exact revenge
Elsewhere, Wawrinka will be looking to atone for his firstround exit to the hands of Fernando Verdasco at the tournament last year.
The world number four’s grass form remains unusually patchy and he carried his disappointment at Queen’s into Wimbledon last year, crashing out in the secondround to the resurgent Juan Martin Del Potro.
However, the Swiss lifted the U.S. Open crown shortly afterwards and was a set away from the Australian Open final last month.
Confidence is certainly not an issue.