Bollywood actor Deepika Padukone, who was issued a summon by the Narcotics Control Bureau (NCB) to join the probe into a drugs case, will join the investigation on Friday.

An NCB source said that Deepika's legal team has informed the probe agency that she will join the investigation on Friday.

The development came a day after the agency issued a summon to Deepika, the daughter of badminton icon Prakash Padukone who is married to Bollywood actor Ranveer Singh, to join the probe after her alleged chats with her manager Karishma Prakash came to the fore during the investigation.

Deepika on Thursday left for Mumbai from Goa, where she was shooting for an upcoming film along with Siddhant Chaturvedi and Ananya Pandey.

Besides Deepika, the agency will also question her manager Karishma. Summons have also been issued to Bollywood actors Sara Ali Khan, Shradhha Kapoor and Rakul Preet Singh for questioning. Sara is the daughter of actors Saif Ali Khan and Amrita Singh, while Shradhha is the daughter of veteran actor Shakti Kapoor.

Rakul was asked to join the probe on Thursday, but she is now set to be questioned by the agency on Friday. Sara and Shraddha have been asked to join the probe on Saturday.

NCB sources said that they all have been summoned after their names surfaced in WhatsApp chats accessed by the NCB and during the questioning of late Bollywood star Sushant Singh Rajput's girlfriend Rhea Chakraborty.

The source said that these celebrities will be questioned about how and from whom they procured drugs and whether they were meant for personal consumption or for someone else.

The source further said that while probing the link of the Kwan Talent Management Agency in the case, Deepika's chats with Karishma surfaced. Karishma handled Deepika's account at Kwan till 2017.

According to an NCB official, the names of Sara and Shraddha came up in two drugs cases registered by the agency.

The official said that the NCB is presently investigating two separate cases which revolve around the drugs cartel that is active in the tinsel town. The first case was registered on the directions of the top brass of the NCB after the Enforcement Directorate (ED) forwarded a brief note on Rhea and her brother Showik's WhatsApp chats.

In its FIR number 15, the NCB claimed, "Analysis of WhatsApp chats of Rhea Chakraborty with other entities reflects the angle of conspiracy and abetment in possession, sale, purchase, consumption, transportation and usage of substances covered under NDPS Act."

In the second case (FIR number 16), the NCB has so far arrested 19 persons, including Rhea and Showik.

Earlier on Thursday, the NCB recorded the statement of fashion designer Simone Khambatta for over four hours while the grilling of Sushant's former manager Shruti Modi is still going on.

The NCB has also recorded the statements of Kwan CEO Dhruv Chitgopekar, producer Madhu Mantena Varma and Sushant's talent manager Jaya Saha.

Sushant was fond dead at his Bandra apartment on June 14.