A fight between Brook and Khan has been mooted for years and it almost came to fruition towards the end of last year.
Khan, though, chose to take a title fight with Terence Crawford, who he comes up against later tonight for the WBO welterweight strap.
Earlier this week, Brook showed up in New York for fight week, making an appearance at the weigh-ins on Friday.
And tonight at the Garden just hours before Brook’s long-time rival Khan takes to the ring, the Sheffield fighter has been shown ringside.
During an undercard fight between Shakur Stevenson and Chrsitopher Diaz, the camera panned towards the crowd.
In the process, it managed to pick up Brook who was sat at ringside with a smile on his face.
The near-sellout crowd erupted into cheers as Brook’s face was shown in the big screen inside the arena.
Brook spoke to exclusively to Express Sport yesterday, noting he thought Khan looked a beaten man when he weighed in.
“It looked like he wasn’t confident to be honest with you,” he said.
“Khan looked like a defeated man, he didn’t look in the best condition.
“Crawford looked really confident to me whereas Khan looked defeated already.
“He didn’t look in the best condition to me and Crawford looked like he was oozing confidence and owned the platform.”
Brook then gave his prediction on the bout, and it was grim reading for Khan and his fans.
“Khan will start fast but he will die out and Crawford will switch it and end it late on before the 12th,” he added.
“I’m after Crawford, Khan is disrespected everybody, the fans want him to fight me and he decided he didn’t want to.
“I think I’ve got the right to fight a guy that will want to fight.”
“Eddie has said about making the fight before but it’s never materialised into anything, I’ve lost patience,” Brook said.