Miranda Lambert is obviously going through a difficult time as it was announced this week that she and Blake Shelton divorced after four years of marriage. The singer was all smiles though on Wednesday night when she surprised a crowd in Nashville.

Lambert showed no signs of heartache when she made an appearance at her friend Ashley Monroe's album release party.

"Miranda looked amazing -- was smiling, happy, dancing, singing,” a source told ET Online. “She is having a great time and is here to support a very good friend."

The 31-year-old singer joined her gal pal to sing "Heart Like Mine," a song they co-wrote with Travis Howard.

Lambert hit the stage in a black dress paired black cowgirl boots.

As previously reported, the last time the country darling was on stage was at a concert in Wyoming where she broke down in tears, prior to the public announcement that her marriage had ended.

Last night either the divorce was the furthest thing from her mind or she put on a very brave face. When the set was over the two friends shared a hug as the crowd cheered.

Image courtesy of INFphoto.com

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