Big Sean sings to Ariana Grande on video when they are apart.

The couple - who have been dating for four months - find being in a long-distance relationship difficult so when their careers mean they can't be together for long periods of time, the 26-year-old rapper ''checks in'' with his 21-year-old girlfriend regularly and his favourite thing to do is send her clips of himself singing to her.

A source told HollywoodLife.com: ''When he's away, he checks in with her all the time, which really helps.

''A few days ago, he made a little video of him singing to her in an elevator. She loves that kind of thing. She just wants to know that even when they aren't together he's thinking of her.''

However, the insider admits things aren't always perfect in the relationship.

They added: ''Ariana and Sean both get jealous sometimes.''

It was recently claimed that Sean ''cut off all communication with the outside world'' and turned off his mobile phone during a short vacation to prove he loved Ariana.

A source said: ''When they were up in Tahoe, he basically cut off all communication with the outside world and gave her his complete and undivided attention.

''He turned off his cell phone for the majority of the day.''

Sean loves taking the 'Bang Bang' hitmaker on romantic trips because he thinks it brings them ''closer''.

The source continued: ''He loves this girl big time and all he wants to continue doing is spending time with her and being lovebirds and incredibly romantic.

''He's got more trips like that in store because he knows she loves that kind of stuff and it brings them both much closer to one another.''