Country rocker Blake Shelton let his girlfriend Gwen Stefani - and the world - know what his favourite song is on her new album.

The 46-year-old No Doubt singer has spoken openly about using her split from husband Gavin Rossdale as inspiration for her latest solo release What the Truth Feels Like. And she admitted that the track Make Me Like You was written about Blake.

Gwen's new beau and fellow coach on The Voice, tweeted: "Hey @gwenstefani... My favorite song on your album is 'Rare'.. Just thought I'd let you know." To which Gwen replied: "@blakeshelton hummmm really ? Wonder who that one is about ? Gx"

With both stars debuting new albums out this year, it seems their romance has struck the right note.

Country superstar Blake's new album, If I'm Honest, makes it appearance next month, but he claims he won't be revealing much about his love life.

"It's not like there's all these juicy details (in the record)" he said in an interview with radio station CMT.

"(Country Music) lends itself to emotions and things that you go through when you go through a divorce and, more so, the getting over that and moving on and finding someone else," he added.

Gwen was replaced on season 10 of The Voice by Christina Aguilera, but returned as a mentor for Blake's group of hopefuls.

It was through mentoring new talent on The Voice that Gwen found the motivation to write new music, as well as introducing her to Blake, who she started dating last November. It followed a difficult period for the star, who divorced her husband of thirteen years in the same year, citing "irreconcilable differences" after Gavin, 50, had a rumoured affair.