Lady Gaga has denied rumours that she and Rihanna have sung a song together for 'ARTPOP'.
"Well, no, that's not true," the 'Marry The Night' hitmaker said in response to a fan's question during an interview with US radio station, KIIS-FM (as quoted here).
"It's a good rumour. I like Rihanna, so, it's just not true."
She did go on to say that she likes hanging out with her though, which is good to know.