NFL star Travis Kelce gave an insight into Princess Charlotte's real personality after meeting her at his girlfriend Taylor Swift's concert.

The three-time Superbowl winner met Prince William and his two eldest children, Prince George and Charlotte, when they attended one of Taylor's sold-out shows at Wembley Stadium. The royal trio enjoyed the three-hour concert from a private box and then got to meet the US pop star and her Kansas City Chiefs boyfriend afterwards.

On his New Heights podcast, which he presents with his brother, Travis revealed how he was left impressed by the heir to the throne and his kids. He said: "[William] was awesome. He was so cool. I didn't realise this because obviously we're backstage meeting him because he was there with little George and Charlotte, and they were an absolute delight to meet."

He dubbed Charlotte the 'coolest' child and said she 'had fire to her' (
Image:
Instagram)
The NFL star said the Princess was 'adorable' and asked lots of questions (
Image:
Getty Images)

He praised nine-year-old Charlotte and called her a "superstar", summing up her personality in five words: "She had fire to her." The sports star revealed she wasn't afraid to ask him or Taylor questions and said she was the stand-out royal.

Calling her the 'coolest' child, he gushed: "Prince William was fantastic, but the highlight was Princess Charlotte. Prince George was great too. She was so f***ing adorable. Like I cannot express how, I don't know, maybe it's because I have three girls now."

Travis explained that he wasn't sure how to greet the royals - whether to "bow to them, curtsy [or] just be an American idiot and shake their hand". But he didn't need to be formal. "They said because we weren't at like an official royal event, we didn't need to bow or curtsy," he shared.

"If it would have been like an official meeting of royalty event, then it would have been that. But I did still address him as Your Royal Highness. And I've never felt emasculated."

On the podcast, Travis also opened up about Taylor's infamous karaoke session with the Prince. The trio performed Livin' On A Prayer at the Winter Whites Gala evening at Kensington Palace, where William jokingly played the air guitar and high-fived everyone on stage.

Travis added: "Bon Jovi called them up and said, yeah, Living on Prayer was a song, I guess Prince William loves to sing karaoke, too. And so Bon Jovi called them up and was like, 'Yo, why don't you come on up here and sing this one with me?' And I guess he was like, 'I don't know'."

"And Taylor was just like, 'Let's do this. I'll roll up there with you. You won't be the only one'." He went on to say that Taylor got Prince William 'out of his shell' and he 'went up there and they ripped it and they said he had a blast.'