Meghan Trainor calls her husband ''Serial Killer''.

The 'All About That Bass' hitmaker and her siblings refer to Daryl Sabara - who she wed last December - by the unusual moniker because of his ''crazy'' appearance and occasional ''suspicious'' behaviour.

Speaking on 'A Little Late with Lilly Singh', she said: ''If you date or marry me -- which he did -- you gotta kinda marry my brothers, as well, and we call him Serial Killer.

''I'll be like, 'Hey sugar' or some weird stuff, but when we're talking about him, it's 'Serial Killer' because he looks crazy in a lot of pictures.

''But also he does suspicious things that we're like, 'Are you a serial killer and we just haven't figured it out yet?'

''He'll go to the movies by himself -- not just one movie, but four back-to-back. Like solo dolo, by himself.

''And he never has sauce on anything, not even salad! Just dry! I begged him, 'Just try this sauce, is it the wrong sauce?' and he's like, 'I like the grass taste' and I was like, 'You're crazy!'''

''Meanwhile, I'm like four dips, each one.''

But the 25-year-old singer insisted she is the 'Spy Kids' actor's ''number one fan'' and thinks her 27-year-old spouse is the nicest person she's ever met.

She gushed: ''I am his number one fan. He's the most supportive human being ever and the nicest guy in the world. Like, you won't believe how nice he is.''

Meghan previously admitted her life feels like a ''fairy tale'' since she married Daryl because he makes her feel so special.

She said: ''Every day feels like our first date. He treats me like a queen. My life is like a fairy tale.''