On Saturday, October 27, McPhee, 34, moaned on Instagram that vocal issues have caused her to have to reschedule the concerts.
The former American Idol competitor and Scorpion actress was set to start her ten-show tour in November.
But she wrote on Instagram, in a lengthy post, "Hi Kids! I've been so looking forward to getting on the road and seeing all your faces for my upcoming tour dates. It's with deep regret that I must postpone these live dates until next year."
McPhee, who recently performed in the musical Waitress in New York, continued, "I've been struggling with extreme vocal fatigue these last few weeks following my Broadway run and have been on strict vocal rest for weeks in hope that I could be ready for this tour come November, but it looks like my body is going to need a little more time."
The star who is planning to wed famed composer/arranger Foster, 68, called the situation "frustrating" and noted that vocal injuries "are a hard thing to explain. I am able to socialize and live my life but I have to do it in total silence."
McPhee, known for reinterpreting classic songs such as "Someone to Watch over Me," hopes to sing onstage again in 2019.
Meanwhile, will she now have down time to plan a wedding to Foster? The May/December couple got engaged in July in Capri, Italy.
McPhee has flaunted her huge diamond engagement ring from Foster on Instagram.
Sadly, McPhee's dad Daniel passed away recently and won't be able to walk her down the aisle when she marries "I Have Nothing" co-writer Foster. But the pretty songstress said her father had approved of her relationship with the much older music veteran.
Foster's daughters have laughed about the age difference, but also have embraced McPhee as their stepmom-to-be.
They have said he and McPhee haven’t yet set a date for their nuptials.
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