Sir Elton John and Lady Gaga are long-time friends and duet partners, but now they have taken their collaboration one step further – as Sir Elton is working with Gaga on her new album.

In an interview on Tuesday, Sir Elton told Zane Lowe on online radio station Beats 1: “I’m writing with Gaga tomorrow.”

Lady Gaga and Elton John
Lady Gaga and Sir Elton John (Jason DeCrow/AP)

He added: “I’ve heard two songs, which are killer. They’re just great songs. It’s like back to the early stuff of hers – like You and I and the Bruce Springsteen one (as I always call it), Bad Romance.”

The two previously teamed up at the 2010 Grammy Awards for a medley of Your Song, and also performed together for the animated film Gnomeo & Juliet and for Gaga’s Muppets Thanksgiving special.

Like any good friend, he had some friendly criticism – calling her out for “bad creative [decisions]” for her third album ARTPOP.

“ARTPOP was not a great idea,” he said, according to Digital Spy. “It was not a good album and I think she would admit that.

“Then in the midst of that, she did three things which were kind of amazing. She did the whole tour and album with Tony Bennett, which did amazingly well. She sang the Julie Andrews tribute at the Oscars, which everybody loved. And she was on American Horror Story.

“I think she’s a great writer. To me, she is Stefani Germanotta and I love her and I care about her – she’s godmother to my two children. And I want her to go and make a kind of simple, fabulous, great song record. Maybe like Tapestry, but her version.

“I’ve heard two of the songs and they’re not complex… They’re not complex arrangements, but they are great songs. It’s all about the song.”

Gaga’s fifth studio album will be released later this year.