MATT LAUER anger levels rise, says insider, in the wake of a Today show top exec switcheroo. Will he HULK out?

Lauer and his new boss, executive producer Alexandra Wallace, have had a very tense relationship and Lauer disagrees on the direction Wallace will be taking with the embattled morning show, a source told

Wallace is an NBC News VP and the first woman to helm TODAY in its 60-year history and is replacing Jim Bell who’s been held accountable for the Ann Curry-Savannah Guthrie debacle.

Wallace has also maintained a very close relationship with Ann Curry, whose relationship with Lauer is frosty at best.

Curry's departure triggered TODAY's ratings crash and enabled ABC's Good Morning America to knock TODAY out of the No. 1 spot it held for years.

"Matt Lauer is NOT happy that Jim Bell who had been the executive producer of the TODAY show since 2005 has been forced out," the source said.

 "Alexandra Wallace, who will be Bell's replacement, and Matt have never had a good working relationship. Matt doesn't like the fact that Alexandra is a big advocate of Ann Curry's.

 "Alexandra is going to be shaking things up on the show in order to get it back on top. For instance, against Matt and Jim Bell's long-time stance of only having NBC-paid experts to comment on current events in the news, which has made the show feel very, very stale, Alexandra plans on using non-NBC staffers to do that.

“The reason is that having different experts will give the audience a much more diverse and knowledgeable base of information they can use in their own lives that isn't the same predictable information being dispersed.

"The fact that Bell is being forced out, and the timing of it during November sweeps shows how desperate NBC executives are for the TODAY show to get back to first place, and quickly," the source said.

Wallace will be the first female executive producer of the TODAY show and "is widely respected by the TODAY cast and crew, sans Matt."