Shawn Mendes says songwriting is the ''best thing next to love''.

The 'Treat You Better' hitmaker has a whole host of self-penned songs to his name and he loves being able to express himself through his music.

Taking to Twitter, he wrote: ''Song writing is the best thing ever next to love! Thats why it coexists so easily with it! (sic)''

Meanwhile, Shawn has been getting advice from John Mayer, who critiqued all the songs on his new album 'Illuminate'.

He shared: ''I didn't get to work with him, but he listened to a bunch of the songs and gave great pieces of advice through the music and production and lyrics and stuff, especially on songs like 'Three Empty Words' and 'Ruin' and 'Patience.' It was great to have him listening through it all.''

Describing his new album as a ''game-changer'', Shawn added: ''I'm very excited ... it's a game-changing album. Honestly, I've never felt so proud of something in my life. It's totally, for me, the experience making it in the studio this time around was life-changing.

''I really got to link up with the perfect people. Jake Gosling, who worked on some of the Ed [Sheeran] records ... like, 'Thinking Out Loud', and he's phenomenal. We spent a few weeks up in upstate New York. It's working so well. We write the songs, they're being produced ... to make it feel easy, it's such a good feeling.''

And the 18-year-old singer believes he has become a ''lot more self-aware'' since he found fame.

He explained: ''I think the biggest thing is how I feel about myself, I think I'm a lot more self-aware. I've never been more judgemental about everything that I do; I'm being a self-critic.

''I think, like, this has made be a little too aware, to the point where I feel it gets to me sometimes. Sometimes I wish that I could just turn my brain off, just tune out, turn it all off for a second.''