(60 Minutes) Harry and Meghan marry on May 19. Where and what time is the wedding taking place?
He told Express.co.uk: "I don't think any particular rules apply here and I don't think there will be the slightest chance that anyone would upstage Meghan at her own wedding".
The biggest challenge for Markle will be "just putting up with it", said the outspoken feminist.
"You have got someone who is going to absolutely stun us with whatever dress she chooses and also as the first American princess, it will be a unique wedding - no-one will upstage her".
The "Walking Away" hitmaker said: "Listen, if I got invited to witness one of the most biggest talking points of modern history when it comes to the royal family, it would be wonderful to be there".
The future wife to Prince Harry appears to be crossing some to-do items off her list before the ceremony.
"As a royal town it is part of who we are to play host to global events just like the royal wedding and I look forward to the world's eyes once again turning to Windsor on 19 May".
Tyler and TJ are the sons of Meghan's half-brother Thomas Markle Jr.
And Mr Fitzwilliams said Harry and Meghan are unlikely to be under obligation to invite Pippa - or any expected guest for that matter.
The likes of Erdem, Christopher Bailey and Ralph & Russo, who designed Markle's $100,000 dress seen in her engagement photos, have all been rumoured to be doing the honours.
Asked what hope she holds for the couple's union, Ms Greer's prediction was bleak.
Castigliano went on: "I think having a lace dress with lovely beading will create more of an element of a today bride, more modern".