Buckingham Palace has shared a message from Queen Elizabeth II to mark the start of celebrations for her Platinum Jubilee, which marks 70 years on the throne.

“Thank you to everyone who has been involved in convening communities, families, neighbours and friends to mark my Platinum Jubilee, in the United Kingdom and across the Commonwealth,” the queen said in the message, also shared in the official Platinum Jubilee program. “I know that many happy memories will be created at these festive occasions.”

“I continue to be inspired by the goodwill shown to me, and hope that the coming days will provide an opportunity to reflect on all that has been achieved during the last seventy years, as we look to the future with confidence and enthusiasm,” she said.

The queen signed her message with her first name, Elizabeth, followed by the letter R, which stands for Regina, the Latin word for queen.

A specially commissioned portrait of Queen Elizabeth II was released Wednesday in the kick-off to her Platinum Jubilee celebrations.

The portrait was taken in the Victoria Vestibule at Windsor Castle on May 25, according to Buckingham Palace.

In the background of the portrait, by Ranald Mackechnie, viewers can see Windsor Castle’s Round Tower, and a statue of King Charles II, according to the palace.

A festive spirit is in the air in the U.K. as it prepares to celebrate its monarch, Queen Elizabeth II, with a once-in-a-lifetime event.

In London, six portraits of the queen are being projected onto the iconic Marble Arch, a 19th century ceremonial gate originally designed as the state entrance for Buckingham Palace, which now resides at the nearby Hyde Park.

Another landmark, Stonehenge, in Wiltshire, England, is also displaying portraits of the queen, one from each decade of her reign.

Collector’s items are also popular for this historic celebration, from souvenir mugs and medals to stamps, handkerchiefs, socks and even a limited-edition Barbie doll.

The Royal Mint has also released a special coin collection to mark the queen’s 70th anniversary.

Queen Elizabeth had a bumpy flight back to England ahead of the four-day public celebration of her Platinum Jubilee. The queen’s flight from Scotland -- where she had enjoyed a four-day break at her Balmoral estate -- had trouble landing due to lightning.

“The Queen’s flight was delayed due to a lightning storm, all the correct procedures were followed and there were no safety concerns,” a Buckingham Palace spokesperson said in a statement.

The queen was later photographed being driven to Windsor Castle.

Queen Elizabeth is expected to make her first public appearance for the festivities on Thursday, when she joins members of the royal family at Trooping the Colour, her annual birthday parade.

People in the U.K. are taking to the streets to celebrate the queen’s Platinum Jubilee, marking 70 years on the throne.

Thousands of street parties are being held over the four-day holiday weekend.

Prince Charles and his wife Camilla, Duchess of Cornwall took to Twitter to thank the public for their celebrations. “We have been touched to see so many people lining the streets," they wrote.

People around the world can also join in the celebration by trying recipes beloved by the royal family.

A 7-layer lemon Swiss roll and amaretti trifle that won the jubilee’s Platinum Pudding Competition is the perfect way to celebrate Elizabeth’s 70 years on the throne.

The pudding, or dessert, was made by amateur baker Jemma Melvin, 31, of Southport, and beat out over 5,000 entries.

If you prefer to celebrate with a tea party fit for a queen, Carolyn Robb, a former chef for the royal family, shared recipes with “Good Morning America” from her book, “Tea at the Palace.”

And if you would like to try scones specifically made for the queen, try this recipe for royal fruit scones made by Mark Flanagan, the personal chef to the queen and the head chef of the royal household.