Singer wrote on Instagram: 'He gave me his heart on Valentine's Day'
Popstar uploaded photos of herself and the Beatles man in the studio together
Photo of Gaga with Chic star was posted onto Twitter
The information emerged during an interview with Howard Stern
Singer performes her take on track at Vienna gig
Duo to perform tracks from recently-released collaboration album 'Cheek to Cheek'
Gaga’s friend popped the question during ArtRave show at the Phones 4 U Arena
Gaga says she "had really awful experiences with men in the studio"
Singer recently collaborated with Tony Bennett on 'Cheek To Cheek'
Gaga's fans are dubbed 'Little Monsters'