Song from Castle tv show

[dum_dum_pops]

The tv show Castle on ABC just started 10 minutes ago and I loved the song in the very beginning but I googled some lyrics from it and couldn't find it. It was a male singer that had a soft voice, kind of like Tom from Plain White Tees. Some of the lyrics were:

I don't know anything without you
I don't know anything about you
we go together like jam and butter (I think)

Please help me out! Thanksssss :)