They've been reunited at Comic-Con but it seems its not all smooth sailing between Jennifer Lawrence and ex-boyfriend Nicholas Hoult. The former couple are currently in San Francisco to promote the X-Men franchise and were reportedly spotting having an argument in a restaurant in the city this week. According to Grazia, Hoult has been attempting to win over his ex while they are filming X-Men: Apocalypse and has been putting pressure on the Oscar-winner to dump Coldplay rocker Chris Martin and give their relationship another try. "They have become inseparable. Nic and Jen have frequently been seen in close conversation, and linking arms during breaks in scenes. In many ways, they're falling into old patterns. At one stage, Jen talked about plans for Chris to visit the set in late June, but in recent weeks she's barely mentioned him." However, Star Magazine is now reporting that Hoult opened up about his feelings for Lawrence over dinner this week and the exchange ended up in a public row between the pair. "Jen was clearly upset with the topic of conversation. She angrily threw her hands up in the air as she yelled at Nick. Next thing you know, he starts screaming too. It was quite a heated argument – she finally walked out on him," a source told the publication. "After Comic-Con, it's going to be interesting to see how they handle working so closely. Jen is a professional, but it's hard to say how Nick and his wounded ego will fare having to act alongside her in such tight quarters,"