Not sure if she's been on but very interesting and has some nice duets.
Beth Hart - Mama (Live at Paradiso) - YouTube (http://www.youtube.com/watch?v=OcgMcO_3Rv4&feature=related)
Something's Got a Hold on Me ~ Beth Hart, Joe Bonamassa at the Echoplex, 9/19/11 - YouTube (http://www.youtube.com/watch?v=kQjXlLWSZPE&feature=related)
SLASH and BETH HART - Whole Lotta Love - George Lopez's HELP HAITI - YouTube (http://www.youtube.com/watch?v=Vz2bIsXuo4I&feature=related)