WHY KATE MIDDLETON DIDN'T ATTEND TAYLOR SWIFT'S ERAS TOUR WITH PRINCE WILLIAM

There were a couple royal blank spaces where Kate Middleton and Prince Louis should have been during night 1 of Taylor Swift's Eras Tour in London.

On Friday, Prince William and joined by his and Kate's two oldest children, Princess Charlotte, 9, and Prince George, 10, for the first show of the GRAMMY-winning singer's London run at Wembley Stadium, and Kate and Louis were noticeably absent. 

ET has learned that Kate, 42, stayed home with Louis, 6, while William, George and Charlotte shook it off during the star-studded concert. According to a source, Kate -- who made her public debut following her cancer diagnosis during last week's Trooping the Coulor -- will not attend any future shows. 

"Princess Kate is not expected to attend any future Taylor concerts. Her appearance at the King's Trooping the Colour doesn’t mean she is returning to a full schedule of public engagements yet, the source says. 

In March, the Princess of Wales went public with her cancer diagnosis. 

On Friday, both William and Swift celebrated the evening with pics. The heir to the British throne took to his official social media platforms to share a selfie of him and his two oldest children with the "Blank Space" singer.

"Thank you @taylorswift for a great evening! #LondonTSTheErastour," the caption next to the photo of Swift holding the phone while William, George and Charlotte flash smiles for the camera behind her. 

The source notes that the photo, was taken ahead of Friday's concert, before the GRAMMY-winning singer took the stage. 

In turn, Swift took to her social media to share another selfie of her, the royals, and boyfriend, Travis Kelce. 

"Happy Bday M8! London shows are off to a splendid start 🇬🇧🇺🇸🤝 @princeandprincessofwales," she wrote. 

The pic also marked her and Kelce's first Instagram grid moment. 

Inside the show, William couldn't contain his excitement as he was seen bopping around to "Shake It Off." 

William's been a Swiftie for some time. You'll remember he and Swift took the stage alongside Jon Bon Jovi back in November 2013 at the Centrepoint Gala Dinner at Kensington Palace in London where they belted out "Livin' on a Prayer."

London has brought the star power, as Swift's concert has been attended by various celebrities including Ashton Kutcher and Mila Kunis, Tom Cruise, Jason and Kylie Kelce and Hugh Grant, during the first two nights. 

Swift's final run at Wembley for this leg with be on June 23. The "London Boy" songstress will make her return for five more shows at the venue through Aug. 15-17 and Aug. 19-20.

For more celebs at the London Eras Tour, click below.

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