Katy Perry has been reflecting on her ''winning'' year as 2018 approaches.

The 33-year-old singer has taken to her Instagram account to discuss her success over the last 12 months, which has seen the launch of her chart-topping fifth studio album 'Witness' and her newfound ambition to make ''purposeful pop''.

In a lengthy post alongside a clip of herself in the video for her new single 'Hey Hey Hey', Katy wrote: ''Hiya. I'm writing you from Miami, prepping my last Witness: The Tour show of 2017. I'm reflecting on a year that has redefined what winning means to me. And the definition of winning for me this year was simply happiness and gratitude. This year has made me more appreciative than ever for my listeners, my KatyCats - whether you've been with me since ''I Kissed A Girl'' or if you only started to ''Swish Swish'' with me. I'm humbled that you still give me your nights out to connect with you live all over the world and remind me of the place in your hearts that you hold for all these songs. (sic)''

Katy also described her latest single as a ''stocking stuffer'' ahead of Christmas.

She said: ''After a year of peaks and valleys (remember, it's all a journey), I wanted to end 2017 with a fun, triumphant piece of pop candy. Just think of it as a glam little stocking stuffer from me to you. ''Hey Hey Hey'' is one of my favorite songs from ''Witness'' and for me, it embodies the fighting spirit I always want you to be able to find within yourself, and to see in me.

So ho, ho, ho; and hey, hey, hey; and happy holidays. (sic)''

Katy revealed her ambition to make more purposeful music earlier this year, saying it's important to spark difficult conversations at this point in history.

Of her single 'Chained to the Rhythm', she previously explained: ''I think it's just, like, a song that starts conversations, and I think that's what we need more than ever ... There's so much divisiveness and people on one side or the other, and I think we just need to listen to each other. I hope this song does that.''