Lady Gaga has commended Lily Allen for being "very sweet", after she defended the poor sales of ARTPOP.
Lily supported Gaga's latest album, and said she should be "commended" for staying true to herself.
The Poker Face singer told BBC Radio 1's Scott Mills: "That's very sweet. I've always been a very big fan of hers and I appreciate her standing up for artists and for me in particular, that's really admirable for her to do that.
"I thought that was very sweet, so thank you Lily, you're lovely," she added.
She also called for musicians to support each other and not become rivals.
"I think all artists should stand by one another," she said.
"When it becomes a competition then we're not supporting creativity and art, but when you support one another wholeheartedly then you're supporting everyone and anything to make what they love," she added.
Lily previously said: "If she's not succeeding commercially because she's standing by what she does as art, then that's a f***ing great thing. That's to be commended. That's what makes a martyr. There's nothing wrong with that."