WATCH: Queen Elizabeth II's coffin lowered into vault as she's laid to rest alongside her husband

Queen Elizabeth II has finally been laid to rest in a private burial service inside Windsor Castle surrounded by her loved ones.

An emotional King Charles III, who was fighting back tears as a rousing rendition of the national anthem filled St George's Chapel, placed the Queen's Company Camp Colour of the Grenadier Guards on the coffin.

With that, Her Majesty was lowered into the Royal Vault underneath the chapel, joining her father George VI and her husband the Duke of Edinburgh.

It marks the final time her coffin will be seen in public, after 11 days of national mourning.

Hundreds of thousands of people crammed into London to pay their final respects to the late Queen, lining the streets for one last glimpse of the monarch's coffin.

At 7.30pm (6.30am NZT), members of the royal family conducted a private burial service behind closed doors and the family entered seven days of their own mourning.