Twenty-two people died in the suicide bombing attack last month and dozens more were wounded.
The couple will use their restaurant's one-year anniversary to "stand in solidarity" with the victims and the families of victims of the attack.
Tobias Roebuck-Ward said winemakers had donated to the evening and there was also an auction with AJ Hackett-sponsored giveaways and accommodation at local hotels.
"We won't be charging for any food or drink, it's entirely voluntary and we are hoping to raise some big bucks from it." Tobias Roebuck-Ward said.
"It's an opportunity to get together and prove that love trumps hate."
The couple had organised the concert before Saturday's London attack.
Following the news, Roebuck-Ward said he and his husband were "heartbroken".
"For people to feel unsafe about being able to go to a concert, a dinner or even just a beer in the pub because of terrorism is terrible.
"We want our event to be seen as a stand against hate. Our community is built up of different people. Each a different colour.
"Tomorrow evening our restaurant will be full of every colour of our community to spread our message of love and inclusivity."
The pair, who married in February, said they celebrate diversity through their restaurant.
At the time of the US Presidential elections they asked their Facebook audience: Want to make the weekend great again?
Then went on to state Adam Arnold welcomes every social, cultural, political, religious or sexual identity.
The couple are also finalists in a new Toyota car competition where they picked six random strangers off the street to take them back to Adam Arnold for a sit-down meal.
"It was a lot of fun and it was all about bring people together and sharing a meal which is what we are all about," Brad Roebuck-Ward said.
