The coach on the show will perform alongside his finalist from this year's series, Lydia Lucy.
The singer made it through to the final back in April but was beaten to the win in the public vote by Kevin Simm.
On the live show Will had promised fans a free gig if Lydia won and even though she didn't quite manage it the concert is still going ahead.
There will be both an evening (5PM) and late night performance (9PM) on May 11 at the Royal Albert Hall with completely free tickets having already been snapped up.
Chatting about her time on the show recently, Lydia said: "I feel absolutely overwhelmed and happy that I made it to the final.
“It has been an amazing journey.”
She added to the Romford Recorder about singing the free gig with Will: “There are not many details at the moment but I am really excited that I will get to sing with Will again."
Speaking during The Voice UK's live final last month, Will vowed to viewers that he would work hard to help Lydia become a "superstar."
"I love the show, we have to make sure that someone's a superstar and has a song in the top 10..." he told hosts Marvin Humes and Emma Willis. "I'm trying my hardest to make that happen."