Can you have a professional relationship with your ex? Most would say 'No'. Working with someone you are or were involved with romantically may have an impact on your job. Besides, even if the breakup is amicable (like that ever happens!), it’s kinda weird to still be in touch with your ex. But that only applies to normal folks. B-town, on the other hand, has no issues with the ex-factor, especially since it makes for good publicity. Take Robert Pattinson and Kristen Stewart in Hollywood, for example, whose reunion for the fourth installment of Twilight after their break-up was highly publicized. While in their case, their contracts tied them together, these Bollywood celebs chose to work with their exes.
Ranveer Singh and Anushka Sharma

Ranveer Singh and Anushka Sharma in Dil Dhadakne Do - BookMyShow
The duo dated while shooting for the actor’s debut movie, Band Baaja Baaraat, where they play friends who become business partners and ultimately fall in love. After the movie, the couple had a rocky relationship for three years, until they finally parted ways for good. But that did not stop them from reuniting in Dil Dhadakne Do, where they played lovers again. 
Deepika Padukone and Ranbir Kapoor

Deepika Padukone and Ranbir Kapoor - BookMyShow
The two actors began dating after working together for Bachna Ae Haseeno, where a Casanova (Ranbir) falls for Deepika’s character. Unfortunately, the couple broke up after Ranbir’s rumored affairs started making headlines. But they remain good friends and even starred opposite each other in Yeh Jawaani Hai Deewani and Tamasha
Katrina Kaif and Ranbir Kapoor

Katrina Kaif and Ranbir Kapoor in Jagga Jasoos - BookMyShow
After being in a serious relationship for many years, the couple recently had a bitter breakup. The two actors have not been spotted together ever since, and even avoid each other at parties, except when they’re shooting for their upcoming movie, Jagga Jasoos. It remains to be seen whether Ranbir and Katrina will work together again in the future.
Salman Khan and Katrina Kaif

Salman Khan and Katrina Kaif in Ek Tha Tiger - BookMyShow
Katrina has always had an amicable relationship with her fellow actors and ex-boyfriends. And sometimes, they happen to be the same. The actress made a cameo appearance in Salman Khan’s Bodyguard, after she had broken up with him. The two actors even starred opposite each other in Ek Tha Tiger
Shahid Kapoor and Kareena Kapoor Khan

Shahid Kapoor and Kareena Kapoor Khan for Udta Punjab - BookMyShow
One of the most shocking breakups in Bollywood, Shahid and Kareena made headlines a few years ago, as their relationship ended. But things worked out well for them, as Kareena moved on with Saif Ali Khan, and Shahid got married to Mira Rajput. Now, the ex-lovers are fairly amicable and also worked together for the promotions of their movie, Udta Punjab.