You can Find Look at Rotation to get the direction from the actor to the center, Get Forward Vector from that and use it as the direction for your movement.
For the movement itself a Timeline would work just fine, as @Alwin mentioned. Save the Actor’s Current Location to a variable, make a second variable and make its value = (Current Location + (Forward Vector * Distance)). The distance in this case will be the difference between the radii (radiuses?) of the circles. Use these two variable as A and B respectively with Lerp or Ease.
Edit: you should probably split the Find Look at Rotation result and make a new rotator with X and Y, leaving Z = 0. And make sure to normalize the Forward Vector thereafter.