Susanna Reid has penned an emotional tribute to Her Majesty the Queen on Instagram amid growing concerns for the monarch's health.It follows news on Thursday (September 8) that the Queen has been placed under medical supervision at Balmoral Castle in Scotland.A statement from Buckingham Palace said doctors have grown "concerned" for Her Majesty's health and that she remains "comfortable" at Balmoral.READ MORE:Susanna Reid, 51, hailed 'super sexy' by fans as she shares glam snap ahead of GMBThe full statement read: "Following further evaluation this morning, the Queen's doctors are concerned for Her Majesty's health and have recommended she remain under medical supervision."It added: "The Queen remains comfortable and at Balmoral."GMB host Susanna took to Instagram with a poignant tribute to the monarch, where she admitted she wished the Queen were "immortal".The ITV star shared two beautiful snaps of Her Majesty smiling as she wore her iconic pearl necklaces.One was from many moons ago and saw her sporting her iconic jewel-encrusted crown, with the second showing her clutching her walking stick in a gorgeous blue jumper.Susanna wrote: "No one more likely to be so loved, admired and respected than Her Majesty The Queen and although she cannot be immortal, I think we have always hoped she might be."Fans of the GMB star flooded to the comments to pen thoughtful messages of their own.One fan wrote: "Very true [heart emoji] cannot imagine the monarchy without our Queen."Another said: "Think we all agree on that sentiment, the greatest woman of our time."A third commented: "You’ve expressed my thoughts exactly.