Now Playing: Gov. Christie Pressured to Run

Now Playing: Chris Christie Dodges Question on Presidential Run

Now Playing: New Pressure on Chris Christie

Now Playing: New music from legendary artist Prince is now available on two deluxe versions of 'Purple Rain'

Now Playing: Mistrial after jury deadlocked in the case of University of Cincinnati officer accused of killing an unarmed black motorist

Now Playing: JetBlue flight forced to make emergency landing in due to smoke in the cockpit

Now Playing: A Chicago-area YMCA is being sued after a man who suffered heart pain while swimming is allegedly ignored by lifeguards

Now Playing: Johnny Depp faces backlash after openly discussing a possible assassination of Donald Trump

Now Playing: Trump reacts to Washington Post report that Obama administration was aware of Russia hacking plot

Now Playing: Ugly pups compete in the annual world's ugliest dog competition

Now Playing: Whale surprises boaters off the coast of New Jersey

Now Playing: Little Big Town performs its fan favorite 'Pontoon' live on 'GMA'

Now Playing: 'Making a Murderer' subject scores court win

Now Playing: Dennis Rodman says North Korea visit was 'worth it' amid criticism

Now Playing: What you need to know about the new breast cancer screening rules

Now Playing: Catching up with Little Big Town live on 'GMA'

Now Playing: 'Dancing' pros Maksim Chmerkovskiy and Peta Murgatroyd share family workout tips

Now Playing: Michael Bay says he's getting his 'money's worth' by making Mark Wahlberg perform 'Transformers' stunts

Now Playing: Sean 'Diddy' Combs opens up about his new documentary

Now Playing: Ron Howard takes over 'Han Solo' spinoff movie