Duchess Kate Middleton and Prince William reveal when baby No. 3 is due

It's official, Duchess Kate and Prince William have announced when we can expect the arrival of baby number 3!

Today, Kensington Palace revealed that the new bundle of joy will be joining sister Charlotte, 2, and brother George, 4, in April 2018.

Royal fans are crossing their fingers for an April 29th arrival date to help Kate and William celebrate their anniversary.

Because Kate suffers from Hyperemesis Gravidarum, Kensington Palace announced the royal pregnancy early -- only a few days into September. The condition causes severe morning sickness and dehydration, forcing the Duchess to pull out of a number of engagements, including missing Prince George's first day of school.

Given Kate's state, the Palace postponed part of next month's royal tour of Norway, Sweden and Finland. Instead, Prince William will make the two-day trip to Finland alone in late November, while the two will visit Sweden and Norway in early 2018.

Related: Inside the Duchess' maternity style:

Last month, while Prince William gave a worrisome update on her condition, he did hint that the new baby may be arriving sooner than we thought!

"All the best with the midwifery, I may see you sooner than you think," he told a midwife at a royal engagement.

It seems that the Duchess, however, is feeling better. Last week, she showed off her baby bump in her first engagement since the pregnancy announcement. And just yesterday, the Duchess made headlines for her adorable dance with Paddington the Bear.

Related: Kate dances with Paddington