Blake Shelton -- Toasts to Divorce -- Sings About Sleeping in the Hay (VIDEO)

Blake Shelton was not crying in his beer right before his divorce became final ... he was drinking it, after giving a shout-out to the glory of divorce.

Blake was in New Hampshire last Saturday for a NASCAR race – two nights before he officially unhitched himself from Miranda Lambert.

Blake was full-on celebrating at a karaoke bar after the race, drinking and even grabbing the mic for a rendition of Tracy Byrd's classic, "I'm From the Country." One of the lyrics ... "And when the beds get full we can sleep in the hay. We're from the country and we like it that way." Well, not always.

Before hitting up the karaoke bar, Blake was at a dive bar where everyone raised their shot glasses, but no one knew an appropriate toast ... and that's when Blake chimed in, "Divorce!"