a walk in the park
A task or activity that is easy or effortless to accomplish. I've been running marathons for years now, so this 5K run will be a walk in the park for me. It's clear that the role is a walk in the park for the veteran actor.
walk in the park
Something that is easy to do or accomplish.
walk in the park, a
Easy, without problems or difficulty. This slangy transfer of a pleasant outing to other contexts dates from the twentieth century. James Patterson used it in London Bridges (2004), when a character checks on the safety of his grandmother: “Everything fine there. Walk in the park, right, Nana?” The synonymous walk on the beach is sometimes substituted but is heard somewhat less often.