Kate Middleton, who was on a four-month maternity leave, will resume her royal duties next week, according to reports. The first official assignment of the Duchess of Cambridge after giving birth to daughter Princess Charlotte will be on Sept. 17.

Kate is scheduled to visit Anna Freud Centre, a child mental health research, training and treatment center in London. The next day, the 33-year-old duchess will be seen with husband, Prince William, and brother-in-law, Prince Harry, at the opening ceremony of the Rugby World Cup 2015, which will start at Twickenham in southwest London, Hello magazine reported Tuesday. Following this, she will have several engagements along with William.

After the birth of Kate and William's first child Prince George in July 2013, the duchess resumed her royal duties within two months. However, this time she took a longer maternity leave.

“She felt she came back too soon last time,” a royal source told People magazine. “She wants to have that [family] and enjoy it with George and the new baby.”

Kate rarely made public appearances during her maternity leave. This gave rise to speculation that the duchess was pregnant with a third child and was keeping out of the public eye because of morning sickness. However, these rumors were silenced by a report in Gossip Cop in which a royal source called Kate’s third pregnancy news “rubbish.”