Credit: Andrew Milligan/Getty

It's been a busy year for the royal family!

While Queen Elizabeth is set to welcome two new additions to the royal family in 2011 with the engagements of Prince William and Zara Phillips, she might have one more addition this year.

Peter Phillips, the son of Princess Anne and cousin to Princes William and Harry, and his wife Autumn are expecting their first child around Christmas. Peter's sister Zara, 29, announced her engagement to longtime boyfriend Mike Tindall on December 21.

Although Peter, 33, is 11th in line for the throne, it is safe to say that his child will be the first -- great-grandchild, that is.

The couple married in 2008 and live in Hong Kong where Phillips works for the Royal Bank of Scotland.