Prince William
"That's certainly a central piece to it. But... it's a hard question to answer," the royal said.
Prince William and Kate Middleton released the black-and-white photo on the prince's 11th birthday on Monday.
"You can't say that!"
The NFL star branded the Prince Of Wales the "coolest motherf***er" after meeting him backstage at Taylor Swift's London show last week.
The future monarch spent his birthday with his children at Taylor Swift's London concert on Friday night.
Fans at Wembley Stadium on Sunday night were treated to an unexpected guest.
The new photo comes just one day after the Princess of Wales made her first public appearance in six months.
The Princess of Wales revealed on March 22 that she had been diagnosed with an unspecified kind of cancer.
The Princess of Wales said in March that she'd been diagnosed with cancer following abdominal surgery.
Prince William And Kate Middleton Celebrate Their Wedding Anniversary With A Never-Before-Seen Photo
The Prince and Princess of Wales celebrated 13 years of marriage on Monday.