Two days earlier, the Good Morning Britain host further criticised the duchess saying she had "dropped him like a sack of spuds" after becoming famous.
He claimed it was "weird behaviour", adding that it was "disconcerting".
Piers maintains he was friends with the former actress before she was famous.
Speaking to co-host Susanna Reid, he said: "She just wants to be ever more important.
"Now she's where she wants to be - she's married her prince and she's best mates with the Clooney's and Michelle Obama.
"Meanwhile, poor old dad is on his own, ailing in Mexico."
Piers added, "Maybe she was just on the charge to the top, and anyone in the way got cut - whoosh."
He added pregnant Meghan was in the "disappointing" category of friends for her behaviour, saying it was "not a nice trait" to drop friends.