Doolittle is most recently known for her impressive performances on this year's American Idol competition.
The tour, which kicks off 29 November and wraps up 22 December, will feature songs from Smith's third Christmas release and twentieth album, It's A Wonderful Christmas. The album debuts 16 October.
Smith recorded the album in London's famous Abbey Road Studios in May with a 67-piece symphony before the music was arranged by David Hamilton. He says the music is "epic, symphonic and cinematic".
Smith originally intended to record a classic Christmas album, but when he got into the studio, he was allegedly struck with a 'rush of inspiration' and wrote several pieces of original music.
The album will feature three choirs, one being The Choristers of Reigate St Mary's, a London based boy's choir directed by John Tobin and featuring 16 members in ages ranging from eight to 12 years.
For tour dates, cities and venues for the Christmas tour, go to www.michaelwsmith.com.
