'Knock Knock Live' preview with Ryan Seacrest and Mariano Rivera

Ryan Seacrest and baseball great Mariano Rivera surprised one very lucky fan in Brooklyn Tuesday night. Fox 5 went along for the ride.

In honor of the new FOX show "Knock Knock Live," Seacrest surprised baseball fan Brooke Cortese at her family's Park Slope home. He introduced her to Rivera. Once settled onto the couch inside, Seacrest and Rivera went one step further and surprised Cortese with tickets to this year's World Series!

For Ryan, the moment was full of "adrenaline," explaining that he thought Rivera's involvement "sealed the deal." And Rivera agreed, saying that "it was wonderful" to see the surprise and joy on Cortese's face as he surprised her.

Of course, Rivera played in 13 All-Star games, capping off his career in 2013. And what was going through his mind as he took the mound during his final All-Star Game? Rivera says that it was "amazing" and that he "can't express it." Which just about sums up Cortese's sentiment. Her reaction? "That's not life! That's not real!"

For more surprises, be sure to watch "Knock Knock Live," premiering June 21 at 9 p.m. on Fox 5.