The 26-year-old actor, best known for playing Neville Longbottom in the Harry Potter franchise, opened up with FAULT Magazine recently about the fateful day he heard that his former co-star had died of pancreatic cancer at the age of 69.
"[A producer] was taking me around the studio when the news came through. We were both just completely stunned," Lewis recalled. "But also, to be in the studio when that came through, suddenly every room that I went into, every corridor that I walked down on, I suddenly remembered a story or an image of Alan."
However, being surrounded by memories of the late actor actually helped Lewis deal with the news.
"It got a bit odd. It was quite surreal. But also, powerfully moving as well. It was quite nice to be there. All those happy memories came flooding back and I got quite nostalgic actually," he shared.
Lewis shared a tribute to Rickman when he died five months ago, posting a photo of the two of them to Instagram, which he captioned, "I was at Leavesden Studios today when I heard the news. As I walked through the canteen I thought of Alan queuing up for his lunch with us mere mortals."
"I recalled the trailer in which he offered me some of the greatest advice I ever received about this mad profession we shared," Lewis continued in the caption. "Being back in those corridors made me remember a lot of things and I will treasure those memories all my life. He inspired my career more than he ever knew and I'll miss him."
"He was the best person to go out to dinner with," Mirren recalled. "He was very generous. He always insisted on paying the bill, he was just entertaining and fun and funny and loved going out to dinner and chatting. He loved that."