The Take That star was heavily involved with the monarch's summer 2012 celebrations, which marked her 60 years on the throne - he wrote a commemorative song and organised a tribute show, which took place outside her Buckingham Palace home in London in June (12), and featured Kylie Minogue, Stevie Wonder and Sir Paul MCCartney.
Barlow was subsequently named in the royal's Birthday Honours List, and he is set to receive an Order of the British Empire (Obe) medal.
But before that ceremony, he attended a special event at the Palace in recognition of his contribution to the Queen's special year.
Speaking at the reception, he told the Bbc, "It's probably a night I'll never forget actually. Stood on that stage while everyone sang the National Anthem, I couldn't believe I was there. I was looking around thinking, 'Are we really here? It's totally incredible'."