Hart stopped 34 of the 35 shots he faced in the Flyers' 4-1 victory over the Boston Bruins on Sunday in the first game of round-robin play.
“He doesn’t look 21 to me," Thompson said, according to NBC Sports Philadelphia's John Clark. "He’s pretty poised, even off the ice. He carries himself well beyond his years.
"He reminds me a little bit of a goalie I used to play with in Montreal”
Thompson spent parts of two seasons with the Canadiens from 2018 to 2020. The 6-foot-1 grinder played in front of Carey Price, the franchise's all-time wins leader who's known for his calm and stoic demeanor.
Price was also excellent in his first start of the return, making 39 saves to help the No. 12 seed Canadiens take a 1-0 series lead over the No. 5 seed Pittsburgh Penguins.
After finishing second among netminders in Calder Trophy voting in 2018-19, Hart followed up his rookie campaign with another strong season. The Alberta native posted a 24-13-3 record with a 2.42 goals-against average and .914 save percentage over 43 appearances.