Best uncle ever?

Prince Harry spared no expense after finding the perfect gift to mark nephew Prince Louis' royal christening on July 9, a new report reveals.

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According to Britain's The Sun, Harry shelled out £8,000 -- more than $10,000 -- for a first-edition copy of "Winnie-The-Pooh" by A.A. Milne for brother Prince William's third child.

Harry's hope is to establish a library for Louis, who was born on April 23, in tribute to the baby's late grandmother, Princess Diana, The Sun claims.

"One of Harry''s happiest childhood memories was being read a bedtime story by his mother. She loved all the old classics and Harry had the brilliant idea of starting a little library of first editions for Louis, [big sister Princess] Charlotte and [big brother Prince] George to enjoy as they get older," a friend told the tabloid.

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Harry originally wanted to pick up Lewis Carroll's "Through the Looking Glass," adds the friend, "which was on sale for £24,000, but decided 'Winnie-The-Pooh' would be more suitable for a first tome. 'Robinson Crusoe' was William's favorite book, but Harry loved all things A.A. Milne."

According to The Sun, only 30,000 first-run copies of the 1926 book were printed. It's believed that Harry bought it from London's Peter Harrington Rare Books.

The morning of Louis' baptism at St. James's Palace in London, Kensington Palace announced that Harry, as well as his new bride, Duchess Meghan, would be one of just a handful of family members at the christening.

Joining the newly minted Duke and Duchess of Sussex? Louis' parents, William and Duchess Kate of Cambridge, of course, as well as grandpa Prince Charles and his wife, Camilla, Duchess of Cornwall, and maternal grandparents Michael and Carole Middleton. Louis' pregnant aunt, Pippa Middleton, and her husband, James Matthews, as well as uncle James Middleton were also invited.

The only other guests expected are his six godparents -- William and Kate's pals Nicholas van Cutsem, Guy Pelly, Harry Aubrey-Fletcher, Lady Laura Meade, Robert Carter and Lucy Middleton -- and their spouses. Queen Elizabeth II and husband Prince Philip won't be at this baptism, reports revealed, as the monarch was traveling back from Sandringham, Norfolk.

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Following custom, Louis will wear a handmade replica of the Victorian-era Royal Christening Robe just like his siblings did and will be baptized at the Lily Font with water from the River Jordan.

Afterward, his parents planned to host a small tea party at Clarence House where they will serve slices of their wedding cake. The fruit cake was preserved following their 2011 wedding and was also served at George and Charlotte's christening receptions.