The 22-year-old's leadership qualities meant Tony Pulis gave him the captain's armband last week in Abdoulaye Faye's absence.
Shawcross told The Sentinel: "I definitely didn't expect that. I am the youngest player in the team and there are a lot of experienced players here, including players who have been captains at other clubs.
"It was an honour for me and probably the highlight of my career so far.
"To be a captain so young is a big thing for me and I was delighted to do it."