The 'Florence and the Machine' singer has been taking the US by storm, having performed at the Grammys and the Oscars, and now has a new American best friend.
The 24-year-old British star said that she first became pals with the Gossip Girl actress when she showed up at one of her gigs, and went on to star in the show herself.
She told E! Online, 'Blake actually came to our very first New York show.
'She's been to all of the shows that we've done in America and she flew out to Las Vegas just because I was performing there over the New Year.'
Welch continued, 'She asked if I wanted to come on Gossip Girl and so we were already friends.
'I love Blake. She's a great girl.'