Paul McCartney has written and recorded new music for a series of "audio emojis" on Skype to celebrate Valentine's Day.

The new compositions, which are coupled with moving emoji designs, last just five seconds and can be sent to friends over the messaging platform for free.

The former Beatle created short tunes for 10 emojis, which capture emotions such as "flirting," "blushing," "love" and "lust."

"I thought, you know what, why not? Something fun, and nice and new," McCartney said of the new venture.

"It turned out to be a great laugh at the same time as challenging, as you suddenly realize you've got to compress a musical interpretation of an emotion into less than five seconds.

So with some of them, which were five and a half or six seconds, we had to work out a way to take the front off or just squeeze this or just take that bit out."