Saint & Sofia apartment pants (order one size down). Returns aren’t brilliant though so don’t order too much. Or could possibly get similar from John Lewis.
Not sure about a top but watching with interest. I absolutely love that look/outfit OP my ideal, simple and comfortable pair with sparkly earrings and maybe a nice necklace (job done cool, comfortable and effortless), but I was gobsmacked by the price then realised it was PJ’s.