R&B singer Robin Thicke canceled his US tour at the last minute, because of a vocal ailment, according to reports. “All tour dates must be rescheduled due to doctor-ordered vocal rest until the end of the year,” said a blog posting at his MySpace page. “Thank you for your understanding and support.” The singer/pianist was scheduled to kick off the outing Nov. 11 in Englewood, CO, and visit clubs and theaters from coast to coast through mid-December. There’s no word yet as to when the tour will be rescheduled. Thicke played across the country in the spring to support his latest album, “The Evolution of Robin Thicke,” which reached No. 5 on The Billboard 200 when it was released last year. The set has spawned the platinum-selling song “Lost Without U” as well as the latest single, “Can U Believe,” which is making waves at R&B/hip-hop radio.