According to reports, the messages far surpassed the 10,000 telegrams that the Queen and Prince Philip received after their wedding in 1947.
The pair's wedding on April 29 is regarded as one of the most high-profile royal event of the decade.
The royal couple are said to be overwhelmed by the good will. According to a St. James's Palace source, There has been a vast, vast amount of cards and letters. It was just lovely, they were all supportive messages. There's a team working on it and everyone who wrote in got a response.
The Mirror (Mirror.co.uk) reported that St. James's Palace has also received hundreds of letters from charities asking for support from the couple. Their wedding gift fund raised 1 million pounds for 26 charities.
In fact, as part of the couple's first joint humanitarian efforts, the Duke and Duchess of Cambridge are all set to visit UNICEF's centre in Denmark to distribute food and medical supplies to East Africa on Wednesday.
The initiative is one of the royal couple's first joint humanitarian mission where they will use their appeal to draw the attention of millions across the globe to the plight of the famine-stricken regions in Africa.