Pink gushed over her longtime friend Gwen Stefani.

The So What singer took to Instagram on Sunday to praise the Sweet Escape singer, who opened for her during her two shows at BST Hyde Park in London over the weekend.

“I have known you for a long time and I have looked up to you like a big sister. You’re the coolest, kindest, and you always have the most swag in the room,” Pink, 34, gushed, alongside a photo of the pair.

The Lady Marmalade singer continued, “Thank you for spending the weekend with me. We have so much more to cover. I’m gonna call you tomorrow lol. I love you."

Gwen, 53, reciprocated the love by commenting on the post, “I love YOU! thank you for allowing me to share the stage with u this weekend.”

The Hollaback Girl singer added, “U are such a rockstar, u speak the truth and I am constantly inspired by u !!! cheers to many more moments like this.”

The two artists have worked together on several occasions. In 2018, they performed a duet of No Doubt’s Just a Girl, during Pink’s Beautiful Trauma World Tour stop in Los Angeles.

As part of Pink’s current Summer Carnival Tour, the Hyde Park performances also featured sets from artists such as Gayle, Tinashe, Sam Ryder, Sam Tompkins, Lyra and more.

The next tour date is 28 June in Berlin, Germany. The trek will wrap up on 19 November in Orland, Florida.