Rumours of an imminent royal engagement are growing ever louder.

There's speculation in the UK Prince Harry has already popped the question to actress Meghan Markle.

Correspondent Gavin Grey told Rachel Smalley the announcement of his engagement is a matter of timing particularly when Kate Middleton is about to have her third child.

"So they obviously need to organise the wedding after that, and there is a rumour of a May wedding, and the announcement of the engagement, possibly Tuesday, Wednesday of this week."