Meghan Markle's pal posts cryptic Insta post day before christening - then deletes it

Meghan Markle's best friend - the favourite to become baby Archie's godmother - today posted a cryptic message on Instagram .

Jessica Mulroney deleted her post after just 35 minutes but it's left fans speculating as to what she meant.

The 38-year-old fashion stylist told her 319,000 followers: "I won't be back with my family for a while so this ends the Instagram session of mum losing her [poop-emoji]".

Some royal experts say the message is a huge hint Jessica had flown to the UK ahead of the baptism , which is due to take place on Saturday.

And Hello! reports that she also shared an Instagram post captioned: "Don't take criticism from anyone you wouldn't go to for advice."

And fans took to social media tonight with their theories.

Jessica Mulroney and Meghan Markle attend a showbiz event in Canada in 2016 (WireImage)

"I hope you're going where I think you might be going!! Love love love," one person posted.

"Can't wait to see what you and Meghan have decided to wear for the day!!!"

With odds on just 1/7, the Canadian mum-of-three looks front-runner to be named godmother tomorrow.

Jessica Mulroney posted this on Instagram but deleted it shortly afterwards (Instagram)

Jessica (right) is pictured with Kate Middleton, Duchess of Cambridge (AFP/Getty Images)

It was reported though Meghan and Harry plan to keep Archie Harrison Mountbatten-Windsor’s godparents a secret .

But Wimbledon champion Serena Williams, 37, revealed she she will not be Archie's godmother.

After beating Kaja Juvan in three sets on Court 1 yesterday, the American coyly smiled when asked if she would be at tomorrow's christening.

Royal expert slams Meghan and Harry's 'privileged' approach to the Christening

Meghan watches Serena Williams at Wimbledon - but the tennis player said she isn't going to be godmother (Phil Harris/Daily Mirror)

She said: "No, I'm working on Saturday. But, yeah, so she [Meghan] understands work."

Archie's christening will be a private ceremony in Windsor, Berkshire, on Saturday.

They have also announced that they will release official photos from the day at a later point.

However, the news will disappoint many royal fans who were looking forward to seeing snaps of the Sussexes arrive at the service.

A statement, released by Buckingham Palace today, reads: "Archie Harrison Mountbatten-Windsor will be christened in a small private ceremony by the Archbishop of Canterbury in the Private Chapel at Windsor Castle on Saturday 6 July.

"The Duke and Duchess of Sussex look forward to sharing some images taken on the day by photographer Chris Allerton.

"The godparents, in keeping with their wishes, will remain private."