Judge Howie Mandel revealed his favorite acts from episode 4 of America's Got Talent in his weekly column on Thursday.

Mandel, who writes for Parade discussing America's Got Talent, first highlighted 6-year-old metal singer Aaralyn as being "unbelievable." During the audition Mandel was her biggest supporter out of the four judges, saying that he liked her style of music and was looking forward to seeing her perform again in Vegas.

"There is an audience for that, and the fact that it came out of that adorable little girl is unbelievable," Mandel wrote in his column. "And what they failed to actually show you is that she wrote those songs!"

The clip of her act on YouTube has already crossed the mark of 4 million views.

Mandel also highlighted stand-up comic Taylor Williamson, writing, "When he was doing his act, and when he wasn't doing his act, he's funny."

Though Mandel said he was surprised Williamson hadn't been "seen" before as a comic, he was actually close to being a finalist on stand-up comedian competition show Last Comic Standing on NBC in 2010. Going forward, Williamson could have a built-in fan-base that could get him extra votes.

During their audition, Mandel told singing duo Brandon & Savannah that it would be better to do covers rather than original songs going forward. In his column, he elaborated and wrote that it's a good strategy to pick songs people know since some people would vote just because they like the song.

"Truth be told, the odds are less that you've written a hit song, than you being a good singer," Mandel wrote. 

Mandel also singled out opera trio Forte as "the most surprising and exciting act of the night." He wrote that the group was "moving, talented and wonderful." Since Forte was featured last in Tuesday night's episode and because Mandel singled them out in his column, chances are high that the group will go far in the competition.

Episode 5 of America's Got Talent airs on Tuesday, July 2 at 9 p.m. on NBC.

Watch the fourth episode in full here: