当然可以，定冠词the和指示代词that均为“中位限定词”，所以都可以用在最高级之前，that用于最高级前通常表特指。COCA（美国当代语料库）中有许多这样的例句：
I'm looking forward to know what is that biggest eye.
That most valuable end could be served by multiple strategies to meet the needs of individual learners.
After the end of that longest day, two spacefarers wearing blue jumpsuits stood holding hands beneath a clear night sky.
I think every parent should have the right to decide that most important decision.
...but the rare English surname Rainbow is not derived from that most beautiful of meteorological phenomena...