Initialize class fields in constructor or at declaration?

I’ve been programming in C# and Java recently and I am curious where the best place is to initialize my class fields.

Should I do it at declaration?:

public class Dice
{
    private int topFace = 1;
    private Random myRand = new Random();

    public void Roll()
    {
       // ......
    }
}

or in a constructor?:

public class Dice
{
    private int topFace;
    private Random myRand;

    public Dice()
    {
        topFace = 1;
        myRand = new Random();
    }

    public void Roll()
    {
        // .....
    }
}

I’m really curious what some of you veterans think is the best practice. I want to be consistent and stick to one approach.