Though Pippa Middleton attended a wedding on July 13 without her boyfriend Nico Jackson, sources recently said the couple is still going strong and an engagement is in their near future.

Middleton, 29, was in Vienna, Austria, for the wedding of Chanel brand ambassador Caroline Sieber and Fritz Von Westenholz. She wore a coral Matthew Williamson dress and matching jacket for the ceremony before changing into a black evening gown for the reception. Guests included designers Christopher Kane and Erdem, and model Jacquetta Wheeler, according to My Daily.

Jackson, a 35-year-old stockbroker, and Middleton were first spotted together nine months ago and he was described by a friend as being "incredibly charismatic."

Jackson vacationed on the Caribbean island of Mustique with Middleton and her family back in February, and the couple was photographed holding hands while walking on the beach. They sat beside each other, held hands and kissed while watching the Wimbledon 2013 men's semi-finals on July 5, and In March they were spotted kissing while on a ski trip.

See photos here.

Earlier in July, a source said Middleton told her family she thinks Jackson is "the one."

Speaking to the Mail On Sunday, a friend of the couple said: "An engagement is definitely on the cards." The insider added that Middleton is expected to announce her engagement within months but has been delaying the news out of respect to her sister Kate Middleton, who is due to give birth to her first child any day now. Another source confirmed that Jackson is waiting for the excitement surrounding the royal baby to die down before he proposes.

"The last time Nico spoke about Pippa to his friends back home in Folkestone, he was totally buzzing about her," the friend said. "He is in his element right now. He has never been happier and this is really what he wants."

Tags: Pippa Middleton