Malik Ghulam Mustafa Khar on Monday joined Pakistan Tehreek-i-Insaf (PTI) after a meeting with party chairman Imran Khan.
"I agree with the PTI's manifesto and its leadership," said the veteran politician while speaking highly of the PTI chairman.
Imran Khan on the occasion welcomed Khar to the party.
Mustafa Khar was famously associated with the PPP as one of its founding members. During Zulfikar Ali Bhutto's government, Khar was appointed the chief minister of Punjab. However, he later fell out of favour with the party's senior leadership and was later associated with the PML-F and the PML-N.
"Imran Khan will lead Pakistan into the future," said Khar, and added, "I will stand side by side with Imran Khan, as he struggles for a new Pakistan".
Earlier today, PPP-Parliamentarians President Asif Ali Zardari made scathing remarks against Imran Khan, while addressing a rally in Mardan.
"He [Khan] calls himself a leader of the youth. How can he be a leader of the youth? He is older than me. Bilawal is a leader for the young people," he said, referring to his son and PPP chairman.
In what may be a rebuttal to Asif Ali Zardari's speech, Khan said, "this is not the time for personal attacks. The need of the hour is to unite for Pakistan."
"The privileged class of people in Pakistan has a responsibility on its shoulders, to work harder than the common man, for greater good of the country," said the PTI chairman.