NBC News special correspondent Tom Brokaw was taken to a Charlotte, N.C., hospital Thursday morning after appearing on MSNBC's "Morning Joe." He later tweeted that he was doing OK.

The network says Brokaw felt "light-headed" on the set of the news-talk program, which has been originating this week from Charlotte. "Out of an abundance of caution," he was taken to a Charlotte-area hospital, which was not identified. NBC said he was being evaluated and "is in good spirits."

At about 10 a.m. Eastern, Brokaw posted on Twitter: "All is well Early AM I mistakenly took a half dose of Ambien and made less sense than usual. Made a better comeback than Giants..."

The 72-year-old Brokaw has been keeping a busy schedule of on-air appearances at the Republican National Convention last week and, this week, at the Democratic Convention.

He has served as special correspondent for NBC News since stepping down as anchor of "Nightly News" in 2004.