High-profile artists sell arena tickets in an instant. This is a fact that has been proven time and time over as more popular artists rise through the ranks and become superstars of their own accord, and few have achieved fame, and popularity as quickly as Taylor Swift. The American singer-songwriter sells out arenas in a matter of hours, and her Red tour was no different.

On the London leg of her Red tour, Taylor Swift fans were blessed with a surprise appearance from none other than the British indie and pop superstar Ed Sheeran. With an uproar from the crowd, the duo came together to perform a beautiful rendition of one of Sheeran’s most popular, mellow tracks, “Lego House”. Watch the incredible performance in the video below:

Before bringing Ed Sheeran onstage, Taylor Swift teases the audience for a while by asking them hypothetical questions about a potential surprise guest star. In the clip, the audience is already riled up, so the announcement that Ed Sheeran was about to enter the stage and play a song was enough to tear the roof off of this London venue. When they realized “Lego House” was about to be played, the cheer was deafening.

Taylor Swift and Ed Sheeran seem to be some form of performance powerhouse when placed together. Mutual fans amongst both acts and with a swarm of adoring fans on both sides, fans were sure to be in for a treat when the two started playing together. Surprisingly, the pair haven’t performed together more, but they have both featured on each other’s songs several times. One of the best Swift-Sheeran collaborations is in “Everything Has Changed”:

Despite Taylor Swift being a worldwide sensation who is adored by all of her fans, and capable of selling out arena tours entirely on her own, she is incredibly humble on stage with Ed Sheeran. During their performance, she slowly lowers the volume of her voice for Ed Sheeran’s delicate British vocals to shine through, which is a nod towards the incredible friendship that these two performers have with each other.

Despite their relationship being purely platonic, Ed Sheeran and Taylor Swift have been the subject of much speculation as to whether or not there is something more in the air. Rumors began circulating in 2013 that the two were an item, however, Ed Sheeran has repeatedly denied the claims and reinforces that the two are simply very good friends.

Not only are the pair good friends, but they also look to each other for support as they traverse the problems of stardom, and also explore their musical talents. Ed Sheeran told Zane Lowe that talking to Swift feels like therapy, and takes comfort in knowing that she understands how he feels about certain things. With all the success both of them have in the world, the fact that they also have good friends is a blessing in their hectic, spontaneous entertainment lives.