Taylor Swift and Calvin Harris are writing songs together.

The 25-year-old singer and the 31-year-old DJ, who started dating in March, are reportedly ''slowly becoming each other's muses'' in the recording studio.

A source close to the 'Blank Space' hitmaker said: ''They're crazy about each other, but are really stimulated by their unique approaches to songwriting. They're slowly becoming each other's muses.''

The duo started playing music together during a low-key date night at Taylor's mansion in Beverly Hills, California.

The insider told the US edition of OK! magazine: ''They often end up in fits of laughter, but they've come up with some very interesting melodies and lyrics and she wants to record some of them.''

The couple were first spotted holding hands at a concert in Nashville, Tennessee two months ago and the 'Summer' hitmaker is smitten with the starlet.

A source previously said: ''He is taken with her. They connected properly at the BRIT [Awards] and it's been going on since then. He is such a good guy. He's serious but also very goofy at the same time. She really likes that combination. It's exciting for both of them. It's hard to meet someone in their business.''