Khan stated on his official Twitter page: "Just want to say thank you for all the support and may the best man win on July 14th. Khan Vs Garcia. Mandalay Bay Vegas."
Khan was due to fight Lamont Peterson on May 19 in a rematch for the WBA and IBF titles after the Bolton fighter lost their first collision in December via split decision amid controversial circumstances.
Peterson has appealed against his failed drugs test and Khan is still waiting to find out whether or not he will be given back the belts he lost in the defeat.
Should that happen, or the titles be declared vacant, Khan's fight against Garcia could be a unification contest.
"It's a good fight for me, Danny Garcia is unbeaten so it will be a tough test for me," the 25-year-old Khan told Sky Sports.
"It's a great match-up, the WBC title will be on the line which I'd love to win. We don't know what's going to happen to the other two titles at the moment because the hearing will be in the next couple of weeks and then the governing bodies will make their decision."
Khan said he was still frustrated at being deprived a chance to avenge his December defeat by Peterson, who was awarded a split-decision after Khan was docked two points.
"I'm still angry because I trained so hard for that fight in the Philippines and LA then in the last week it was called off and all my training went down the drain," Khan, who has lost just twice in 28 fights, said.
"I'm still upset because I wanted to win my titles back and settle the score."
Twenty-four-year-old Garcia of Philadelphia is undefeated in 23 fights, winning 14 by knockout, and will defend the WBC title he won in his last fight over Mexican Erik Morales in March.
Morales was stripped of the belt after failing to make weight, before Garcia became champion with a unanimous decision.